feat(external-tools): force tools to open in new windows where needed

Adds a helper that forces selected tools to launch in a new window
instead of reusing the current one. This is applied to code editors,
diff/merge, and terminal launches, aligning behavior across platforms.
Presets and defaults are updated to pass new-window or equivalent flags,
and tests verify the new behavior for common tools.

- Update code editors to always use a new window when opened
- Normalize launch flags for Windows terminals and diff tools
- Add tests covering new-window behavior for common tools

src-tauri/src/external_tools.rs

@@ -405,8 +405,10 @@ fn known_tools() -> Vec<ToolSpec> {
         tool(
             "git-bash",
             "Git Bash",
-            &["bash.exe"],
+            &["git-bash.exe", "bash.exe"],
             &[
+                r"%PROGRAMFILES%\Git\git-bash.exe",
+                r"%LOCALAPPDATA%\Programs\Git\git-bash.exe",
                 r"%PROGRAMFILES%\Git\bin\bash.exe",
                 r"%LOCALAPPDATA%\Programs\Git\bin\bash.exe",
             ],
@@ -1350,6 +1352,101 @@ fn expand_args(
         .collect()
 }
 
+fn command_in_new_window(mut command: ExternalToolCommand) -> ExternalToolCommand {
+    let executable = Path::new(command.program.trim())
+        .file_name()
+        .and_then(|name| name.to_str())
+        .unwrap_or(command.program.trim())
+        .to_ascii_lowercase();
+
+    let remove_flags = |args: &mut Vec<String>, flags: &[&str]| {
+        args.retain(|arg| !flags.iter().any(|flag| arg.eq_ignore_ascii_case(flag)));
+    };
+    let prepend_flag = |args: &mut Vec<String>, flag: &str| {
+        if !args.iter().any(|arg| arg.eq_ignore_ascii_case(flag)) {
+            args.insert(0, flag.to_string());
+        }
+    };
+
+    if matches!(
+        executable.as_str(),
+        "code"
+            | "code.exe"
+            | "code-insiders"
+            | "code-insiders.exe"
+            | "code - insiders.exe"
+            | "cursor"
+            | "cursor.exe"
+            | "windsurf"
+            | "windsurf.exe"
+            | "vscodium"
+            | "vscodium.exe"
+            | "codium"
+            | "codium.exe"
+    ) {
+        remove_flags(&mut command.args, &["--reuse-window", "-r"]);
+        prepend_flag(&mut command.args, "--new-window");
+    } else if matches!(executable.as_str(), "zed" | "zed.exe") {
+        remove_flags(&mut command.args, &["--reuse", "-r"]);
+        prepend_flag(&mut command.args, "--new");
+    } else if matches!(
+        executable.as_str(),
+        "subl" | "subl.exe" | "sublime_text" | "sublime_text.exe"
+    ) {
+        prepend_flag(&mut command.args, "--new-window");
+    } else if executable == "notepad++.exe" {
+        prepend_flag(&mut command.args, "-multiInst");
+    } else if executable == "kate" || executable == "kate.exe" {
+        prepend_flag(&mut command.args, "--new");
+    } else if executable == "geany" || executable == "geany.exe" {
+        prepend_flag(&mut command.args, "--new-instance");
+    } else if executable == "wt" || executable == "wt.exe" {
+        let mut index = 0;
+        while index < command.args.len() {
+            let is_window = command.args[index].eq_ignore_ascii_case("-w")
+                || command.args[index].eq_ignore_ascii_case("--window")
+                || command.args[index]
+                    .to_ascii_lowercase()
+                    .starts_with("--window=");
+            if is_window {
+                let has_separate_value = !command.args[index].contains('=');
+                command.args.remove(index);
+                if has_separate_value && index < command.args.len() {
+                    command.args.remove(index);
+                }
+            } else {
+                index += 1;
+            }
+        }
+        command
+            .args
+            .splice(0..0, ["-w".to_string(), "new".to_string()]);
+    } else if executable == "explorer" || executable == "explorer.exe" {
+        prepend_flag(&mut command.args, "/n,");
+    } else if matches!(
+        executable.as_str(),
+        "totalcmd" | "totalcmd.exe" | "totalcmd64" | "totalcmd64.exe"
+    ) {
+        command
+            .args
+            .retain(|arg| !arg.to_ascii_lowercase().starts_with("/o"));
+        prepend_flag(&mut command.args, "/N");
+    } else if executable == "open" {
+        prepend_flag(&mut command.args, "-n");
+    } else if executable.starts_with("bcomp") {
+        remove_flags(&mut command.args, &["/solo", "-solo"]);
+        #[cfg(windows)]
+        prepend_flag(&mut command.args, "/solo");
+        #[cfg(not(windows))]
+        prepend_flag(&mut command.args, "-solo");
+    } else if executable == "winmergeu" || executable == "winmergeu.exe" {
+        remove_flags(&mut command.args, &["/s", "/sw", "-s", "-sw"]);
+        prepend_flag(&mut command.args, "/s-");
+    }
+
+    command
+}
+
 fn tool_values(repo: &Path, file: Option<&Path>) -> BTreeMap<&'static str, String> {
     let mut values = BTreeMap::new();
     values.insert("repo", repo.to_string_lossy().into_owned());
@@ -1371,11 +1468,10 @@ fn spawn_tool(
     repo: &Path,
     values: BTreeMap<&str, String>,
 ) -> Result<(), String> {
+    let command = command_in_new_window(command);
     let args = expand_args(&command, &values)?;
     let mut process = Command::new(command.program.trim());
     process.args(args).current_dir(repo);
-    #[cfg(windows)]
-    process.creation_flags(CREATE_NO_WINDOW);
     process
         .spawn()
         .map_err(|error| format!("Could not launch external tool: {error}"))?;
@@ -1388,6 +1484,7 @@ fn run_tool(
     values: BTreeMap<&str, String>,
     kind: ExternalToolRunKind,
 ) -> Result<(), String> {
+    let command = command_in_new_window(command);
     let args = expand_args(&command, &values)?;
     let program = command.program.trim().to_owned();
     let mut process = Command::new(command.program.trim());
@@ -1580,6 +1677,62 @@ mod tests {
         );
     }
 
+    #[test]
+    fn forces_code_family_tools_into_a_new_window() {
+        let command = command_in_new_window(ExternalToolCommand {
+            program: "C:/Program Files/Microsoft VS Code/Code.exe".into(),
+            args: vec![
+                "--reuse-window".into(),
+                "--diff".into(),
+                "{left}".into(),
+                "{right}".into(),
+            ],
+        });
+
+        assert_eq!(
+            command.args,
+            vec!["--new-window", "--diff", "{left}", "{right}"]
+        );
+    }
+
+    #[test]
+    fn forces_windows_terminal_to_use_a_fresh_window() {
+        let command = command_in_new_window(ExternalToolCommand {
+            program: "wt.exe".into(),
+            args: vec![
+                "--window".into(),
+                "last".into(),
+                "-d".into(),
+                "{repo}".into(),
+            ],
+        });
+
+        assert_eq!(command.args, vec!["-w", "new", "-d", "{repo}"]);
+    }
+
+    #[test]
+    fn forces_single_instance_compare_and_file_tools_into_new_windows() {
+        let beyond = command_in_new_window(ExternalToolCommand {
+            program: "BCompare.exe".into(),
+            args: vec!["/readonly".into(), "{left}".into(), "{right}".into()],
+        });
+        let winmerge = command_in_new_window(ExternalToolCommand {
+            program: "WinMergeU.exe".into(),
+            args: vec!["/s".into(), "{left}".into(), "{right}".into()],
+        });
+        let total_commander = command_in_new_window(ExternalToolCommand {
+            program: "TOTALCMD64.EXE".into(),
+            args: vec!["/O".into(), "/T".into(), "{repo}".into()],
+        });
+
+        #[cfg(windows)]
+        assert_eq!(beyond.args[0], "/solo");
+        #[cfg(not(windows))]
+        assert_eq!(beyond.args[0], "-solo");
+        assert_eq!(winmerge.args, vec!["/s-", "{left}", "{right}"]);
+        assert_eq!(total_commander.args, vec!["/N", "/T", "{repo}"]);
+    }
+
     #[test]
     fn rejects_unknown_placeholder() {
         let command = ExternalToolCommand {

src/lib/externalTools.ts

@@ -53,15 +53,15 @@ const jetBrains: ToolIdentity[] = [
 ];
 
 const editor = (tool: ToolIdentity, args = ["{file}"]): ExternalToolPreset => ({ ...tool, args });
-const codeDiff = (tool: ToolIdentity): ExternalToolPreset => ({ ...tool, args: ["--wait", "--diff", "{left}", "{right}"] });
+const codeDiff = (tool: ToolIdentity): ExternalToolPreset => ({ ...tool, args: ["--new-window", "--wait", "--diff", "{left}", "{right}"] });
-const codeMerge = (tool: ToolIdentity): ExternalToolPreset => ({ ...tool, args: ["--wait", "--merge", "{ours}", "{theirs}", "{base}", "{result}"] });
+const codeMerge = (tool: ToolIdentity): ExternalToolPreset => ({ ...tool, args: ["--new-window", "--wait", "--merge", "{ours}", "{theirs}", "{base}", "{result}"] });
 const jetBrainsDiff = (tool: ToolIdentity): ExternalToolPreset => ({ ...tool, args: ["diff", "{left}", "{right}"] });
 const jetBrainsMerge = (tool: ToolIdentity): ExternalToolPreset => ({ ...tool, args: ["merge", "{ours}", "{theirs}", "{base}", "{result}"] });
 
 const commonEditors: ExternalToolPreset[] = [
-  ...codeFamily.map((item) => editor(item, ["--reuse-window", "{file}"])),
+  ...codeFamily.map((item) => editor(item, ["--new-window", "{file}"])),
-  editor({ id: "zed", label: "Zed", program: externalToolsPlatform === "windows" ? "zed.exe" : "zed" }),
+  editor({ id: "zed", label: "Zed", program: externalToolsPlatform === "windows" ? "zed.exe" : "zed" }, ["--new", "{file}"]),
-  editor({ id: "sublime-text", label: "Sublime Text", program: externalToolsPlatform === "windows" ? "subl.exe" : "subl" }),
+  editor({ id: "sublime-text", label: "Sublime Text", program: externalToolsPlatform === "windows" ? "subl.exe" : "subl" }, ["--new-window", "{file}"]),
   ...jetBrains.map((item) => editor(item)),
   editor({ id: "neovim", label: "Neovim", program: externalToolsPlatform === "windows" ? "nvim.exe" : "nvim" }),
   editor({ id: "vim", label: "Vim", program: externalToolsPlatform === "windows" ? "gvim.exe" : "gvim" }),
@@ -70,7 +70,7 @@ const commonEditors: ExternalToolPreset[] = [
 
 const platformEditors: ExternalToolPreset[] = externalToolsPlatform === "windows"
   ? [
-      editor({ id: "notepad-plus-plus", label: "Notepad++", program: "notepad++.exe" }),
+      editor({ id: "notepad-plus-plus", label: "Notepad++", program: "notepad++.exe" }, ["-multiInst", "{file}"]),
       { ...editor({ id: "notepad", label: "Windows Notepad", program: "notepad.exe" }), builtIn: true },
     ]
   : externalToolsPlatform === "macos"
@@ -82,16 +82,16 @@ const platformEditors: ExternalToolPreset[] = externalToolsPlatform === "windows
       ]
     : [
         editor({ id: "lapce", label: "Lapce", program: "lapce" }),
-        editor({ id: "kate", label: "Kate", program: "kate" }),
+        editor({ id: "kate", label: "Kate", program: "kate" }, ["--new", "{file}"]),
         editor({ id: "gedit", label: "GNOME Text Editor", program: "gnome-text-editor" }),
-        editor({ id: "geany", label: "Geany", program: "geany" }),
+        editor({ id: "geany", label: "Geany", program: "geany" }, ["--new-instance", "{file}"]),
         editor({ id: "helix", label: "Helix", program: "hx" }),
       ];
 
 const dedicatedDiff: ExternalToolPreset[] = externalToolsPlatform === "windows"
   ? [
-      { id: "beyond-compare", label: "Beyond Compare", program: "BCompare.exe", args: ["/readonly", "{left}", "{right}"] },
+      { id: "beyond-compare", label: "Beyond Compare", program: "BCompare.exe", args: ["/solo", "/readonly", "{left}", "{right}"] },
-      { id: "winmerge", label: "WinMerge", program: "WinMergeU.exe", args: ["/u", "/e", "/wl", "/wr", "{left}", "{right}"] },
+      { id: "winmerge", label: "WinMerge", program: "WinMergeU.exe", args: ["/s-", "/u", "/e", "/wl", "/wr", "{left}", "{right}"] },
       { id: "meld", label: "Meld", program: "meld.exe", args: ["--wait", "{left}", "{right}"] },
       { id: "kdiff3", label: "KDiff3", program: "kdiff3.exe", args: ["{left}", "{right}"] },
       { id: "p4merge", label: "P4Merge", program: "p4merge.exe", args: ["{left}", "{right}"] },
@@ -100,14 +100,14 @@ const dedicatedDiff: ExternalToolPreset[] = externalToolsPlatform === "windows"
     ]
   : externalToolsPlatform === "macos"
     ? [
-        { id: "beyond-compare", label: "Beyond Compare", program: "bcompare", args: ["{left}", "{right}"] },
+        { id: "beyond-compare", label: "Beyond Compare", program: "bcompare", args: ["-solo", "{left}", "{right}"] },
         { id: "kaleidoscope", label: "Kaleidoscope", program: "ksdiff", args: ["--wait", "{left}", "{right}"] },
         { id: "araxis-merge", label: "Araxis Merge", program: "compare", args: ["-wait", "{left}", "{right}"] },
         { id: "p4merge", label: "P4Merge", program: "p4merge", args: ["{left}", "{right}"] },
         { id: "opendiff", label: "FileMerge", program: "opendiff", args: ["{left}", "{right}"] },
       ]
     : [
-        { id: "beyond-compare", label: "Beyond Compare", program: "bcompare", args: ["{left}", "{right}"] },
+        { id: "beyond-compare", label: "Beyond Compare", program: "bcompare", args: ["-solo", "{left}", "{right}"] },
         { id: "meld", label: "Meld", program: "meld", args: ["--wait", "{left}", "{right}"] },
         { id: "kdiff3", label: "KDiff3", program: "kdiff3", args: ["{left}", "{right}"] },
         { id: "p4merge", label: "P4Merge", program: "p4merge", args: ["{left}", "{right}"] },
@@ -116,8 +116,8 @@ const dedicatedDiff: ExternalToolPreset[] = externalToolsPlatform === "windows"
 
 const dedicatedMerge: ExternalToolPreset[] = externalToolsPlatform === "windows"
   ? [
-      { id: "beyond-compare", label: "Beyond Compare", program: "BCompare.exe", args: ["{ours}", "{theirs}", "{base}", "/mergeoutput={result}"] },
+      { id: "beyond-compare", label: "Beyond Compare", program: "BCompare.exe", args: ["/solo", "{ours}", "{theirs}", "{base}", "/mergeoutput={result}"] },
-      { id: "winmerge", label: "WinMerge", program: "WinMergeU.exe", args: ["/u", "/e", "{ours}", "{theirs}", "{base}", "/o", "{result}"] },
+      { id: "winmerge", label: "WinMerge", program: "WinMergeU.exe", args: ["/s-", "/u", "/e", "{ours}", "{theirs}", "{base}", "/o", "{result}"] },
       { id: "meld", label: "Meld", program: "meld.exe", args: ["--wait", "--auto-merge", "{ours}", "{base}", "{theirs}", "--output={result}"] },
       { id: "kdiff3", label: "KDiff3", program: "kdiff3.exe", args: ["{base}", "{ours}", "{theirs}", "-o", "{result}"] },
       { id: "p4merge", label: "P4Merge", program: "p4merge.exe", args: ["{base}", "{theirs}", "{ours}", "{result}"] },
@@ -126,14 +126,14 @@ const dedicatedMerge: ExternalToolPreset[] = externalToolsPlatform === "windows"
     ]
   : externalToolsPlatform === "macos"
     ? [
-        { id: "beyond-compare", label: "Beyond Compare", program: "bcompare", args: ["{ours}", "{theirs}", "{base}", "/mergeoutput={result}"] },
+        { id: "beyond-compare", label: "Beyond Compare", program: "bcompare", args: ["-solo", "{ours}", "{theirs}", "{base}", "/mergeoutput={result}"] },
         { id: "kaleidoscope", label: "Kaleidoscope", program: "ksdiff", args: ["--merge", "--output", "{result}", "{base}", "{ours}", "{theirs}"] },
         { id: "araxis-merge", label: "Araxis Merge", program: "compare", args: ["-wait", "{ours}", "{base}", "{theirs}", "{result}"] },
         { id: "p4merge", label: "P4Merge", program: "p4merge", args: ["{base}", "{theirs}", "{ours}", "{result}"] },
         { id: "opendiff", label: "FileMerge", program: "opendiff", args: ["{ours}", "{theirs}", "-ancestor", "{base}", "-merge", "{result}"] },
       ]
     : [
-        { id: "beyond-compare", label: "Beyond Compare", program: "bcompare", args: ["{ours}", "{theirs}", "{base}", "/mergeoutput={result}"] },
+        { id: "beyond-compare", label: "Beyond Compare", program: "bcompare", args: ["-solo", "{ours}", "{theirs}", "{base}", "/mergeoutput={result}"] },
         { id: "meld", label: "Meld", program: "meld", args: ["--wait", "--auto-merge", "{ours}", "{base}", "{theirs}", "--output={result}"] },
         { id: "kdiff3", label: "KDiff3", program: "kdiff3", args: ["{base}", "{ours}", "{theirs}", "-o", "{result}"] },
         { id: "p4merge", label: "P4Merge", program: "p4merge", args: ["{base}", "{theirs}", "{ours}", "{result}"] },
@@ -141,10 +141,10 @@ const dedicatedMerge: ExternalToolPreset[] = externalToolsPlatform === "windows"
 
 const terminalPresets: ExternalToolPreset[] = externalToolsPlatform === "windows"
   ? [
-      { id: "windows-terminal", label: "Windows Terminal", program: "wt.exe", args: ["-d", "{repo}"] },
+      { id: "windows-terminal", label: "Windows Terminal", program: "wt.exe", args: ["-w", "new", "-d", "{repo}"] },
       { id: "powershell", label: "PowerShell 7", program: "pwsh.exe", args: ["-NoExit", "-WorkingDirectory", "{repo}"] },
       { id: "windows-powershell", label: "Windows PowerShell", program: "powershell.exe", args: ["-NoExit"], builtIn: true },
-      { id: "git-bash", label: "Git Bash", program: "bash.exe", args: ["--login", "-i"] },
+      { id: "git-bash", label: "Git Bash", program: "git-bash.exe", args: ["--login", "-i"] },
       { id: "cmd", label: "Command Prompt", program: "cmd.exe", args: ["/K"], builtIn: true },
       { id: "wezterm", label: "WezTerm", program: "wezterm-gui.exe", args: ["start", "--cwd", "{repo}"] },
       { id: "alacritty", label: "Alacritty", program: "alacritty.exe", args: ["--working-directory", "{repo}"] },
@@ -152,9 +152,9 @@ const terminalPresets: ExternalToolPreset[] = externalToolsPlatform === "windows
     ]
   : externalToolsPlatform === "macos"
     ? [
-        { id: "terminal", label: "Terminal", program: "open", args: ["-a", "Terminal", "{repo}"], builtIn: true },
+        { id: "terminal", label: "Terminal", program: "open", args: ["-n", "-a", "Terminal", "{repo}"], builtIn: true },
-        { id: "iterm2", label: "iTerm2", program: "open", args: ["-a", "iTerm", "{repo}"] },
+        { id: "iterm2", label: "iTerm2", program: "open", args: ["-n", "-a", "iTerm", "{repo}"] },
-        { id: "warp", label: "Warp", program: "open", args: ["-a", "Warp", "{repo}"] },
+        { id: "warp", label: "Warp", program: "open", args: ["-n", "-a", "Warp", "{repo}"] },
         { id: "wezterm", label: "WezTerm", program: "wezterm", args: ["start", "--cwd", "{repo}"] },
         { id: "alacritty", label: "Alacritty", program: "alacritty", args: ["--working-directory", "{repo}"] },
       ]
@@ -171,8 +171,8 @@ const terminalPresets: ExternalToolPreset[] = externalToolsPlatform === "windows
 
 const fileManagerPresets: ExternalToolPreset[] = externalToolsPlatform === "windows"
   ? [
-      { id: "explorer", label: "Windows Explorer", program: "explorer.exe", args: ["{repo}"], builtIn: true },
+      { id: "explorer", label: "Windows Explorer", program: "explorer.exe", args: ["/n,", "{repo}"], builtIn: true },
-      { id: "total-commander", label: "Total Commander", program: "TOTALCMD64.EXE", args: ["/O", "/T", "{repo}"] },
+      { id: "total-commander", label: "Total Commander", program: "TOTALCMD64.EXE", args: ["/N", "/T", "{repo}"] },
       { id: "directory-opus", label: "Directory Opus", program: "dopus.exe", args: ["{repo}"] },
       { id: "double-commander", label: "Double Commander", program: "doublecmd.exe", args: ["{repo}"] },
       { id: "freecommander", label: "FreeCommander XE", program: "FreeCommander.exe", args: ["/L={repo}"] },
@@ -180,7 +180,7 @@ const fileManagerPresets: ExternalToolPreset[] = externalToolsPlatform === "wind
     ]
   : externalToolsPlatform === "macos"
     ? [
-        { id: "finder", label: "Finder", program: "open", args: ["{repo}"], builtIn: true },
+        { id: "finder", label: "Finder", program: "open", args: ["-n", "{repo}"], builtIn: true },
         { id: "forklift", label: "ForkLift", program: "forklift", args: ["{repo}"] },
         { id: "path-finder", label: "Path Finder", program: "Path Finder", args: ["{repo}"] },
       ]
@@ -196,7 +196,7 @@ const fileManagerPresets: ExternalToolPreset[] = externalToolsPlatform === "wind
 
 export const externalToolPresets: Record<ExternalToolKind, ExternalToolPreset[]> = {
   editor: [...commonEditors, ...platformEditors],
-  diff: [...dedicatedDiff, ...codeFamily.map(codeDiff), { id: "zed", label: "Zed", program: externalToolsPlatform === "windows" ? "zed.exe" : "zed", args: ["--diff", "{left}", "{right}"] }, ...jetBrains.map(jetBrainsDiff)],
+  diff: [...dedicatedDiff, ...codeFamily.map(codeDiff), { id: "zed", label: "Zed", program: externalToolsPlatform === "windows" ? "zed.exe" : "zed", args: ["--new", "--diff", "{left}", "{right}"] }, ...jetBrains.map(jetBrainsDiff)],
   merge: [...dedicatedMerge, ...codeFamily.map(codeMerge), ...jetBrains.map(jetBrainsMerge)],
   terminal: terminalPresets,
   fileManager: fileManagerPresets,
@@ -233,14 +233,21 @@ export function defaultExternalToolsSettings(detectedTools: DetectedExternalTool
   };
 }
 
-function normaliseSetting(value: unknown, fallback: ExternalToolSetting): ExternalToolSetting {
+function normaliseSetting(kind: ExternalToolKind, value: unknown, fallback: ExternalToolSetting): ExternalToolSetting {
   if (!value || typeof value !== "object" || Array.isArray(value)) return fallback;
   const candidate = value as Partial<ExternalToolSetting>;
   const program = typeof candidate.program === "string" && candidate.program.trim() ? candidate.program : fallback.program;
-  const args = Array.isArray(candidate.args)
+  const storedArgs = Array.isArray(candidate.args)
     ? candidate.args.filter((item): item is string => typeof item === "string").slice(0, 64)
     : fallback.args;
   const preset = typeof candidate.preset === "string" && candidate.preset ? candidate.preset : fallback.preset;
+  // Preset arguments are application-owned and can be upgraded safely. Editing either
+  // the executable or arguments in Settings changes the preset to "custom", which keeps
+  // genuine user commands untouched.
+  const currentPreset = preset === "custom"
+    ? undefined
+    : externalToolPresets[kind].find((item) => item.id === preset);
+  const args = currentPreset ? [...currentPreset.args] : storedArgs;
   return { preset, program, args };
 }
 
@@ -249,11 +256,11 @@ export function normaliseExternalToolsSettings(value: unknown): ExternalToolsSet
   if (!value || typeof value !== "object" || Array.isArray(value)) return defaults;
   const candidate = value as Partial<ExternalToolsSettings>;
   return {
-    editor: normaliseSetting(candidate.editor, defaults.editor),
+    editor: normaliseSetting("editor", candidate.editor, defaults.editor),
-    diff: normaliseSetting(candidate.diff, defaults.diff),
+    diff: normaliseSetting("diff", candidate.diff, defaults.diff),
-    merge: normaliseSetting(candidate.merge, defaults.merge),
+    merge: normaliseSetting("merge", candidate.merge, defaults.merge),
-    terminal: normaliseSetting(candidate.terminal, defaults.terminal),
+    terminal: normaliseSetting("terminal", candidate.terminal, defaults.terminal),
-    fileManager: normaliseSetting(candidate.fileManager, defaults.fileManager),
+    fileManager: normaliseSetting("fileManager", candidate.fileManager, defaults.fileManager),
     diffOpenMode: normaliseOpenMode(candidate.diffOpenMode, defaults.diffOpenMode),
     mergeOpenMode: normaliseOpenMode(candidate.mergeOpenMode, defaults.mergeOpenMode),
   };