Demonstrate that toggling whitespace undims the panel beneath the main view

Toggling whitespace re-focuses the side panel to re-render the diff, which
also re-derives that panel's highlight — as though the panel had the focus,
which it doesn't.

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

pkg/integration/tests/test_list.go

@@ -530,6 +530,7 @@ var tests = []*components.IntegrationTest{
 	ui.SwitchRepoMovesTheSelection,
 	ui.SwitchTabFromMenu,
 	ui.SwitchTabWithPanelJumpKeys,
+	ui.ToggleWhitespaceKeepsUnfocusedSelectionDimmed,
 	ui.UnfocusedListHidesSelectionWhenEmptied,
 	ui.UnfocusedListShowsSelectionWhenFilled,
 	undo.UndoCheckoutAndDrop,

pkg/integration/tests/ui/toggle_whitespace_keeps_unfocused_selection_dimmed.go

@@ -0,0 +1,34 @@
+package ui
+
+import (
+	"github.com/jesseduffield/lazygit/pkg/config"
+	. "github.com/jesseduffield/lazygit/pkg/integration/components"
+)
+
+var ToggleWhitespaceKeepsUnfocusedSelectionDimmed = NewIntegrationTest(NewIntegrationTestArgs{
+	Description:  "Toggling whitespace from the main view leaves the panel beneath it showing a dimmed selection",
+	ExtraCmdArgs: []string{},
+	Skip:         false,
+	SetupConfig:  func(config *config.AppConfig) {},
+	SetupRepo: func(shell *Shell) {
+		shell.CreateFileAndAdd("file1", "one\n")
+		shell.Commit("one")
+		shell.UpdateFile("file1", "  one\n")
+	},
+	Run: func(t *TestDriver, keys config.KeybindingConfig) {
+		t.Views().Files().
+			IsFocused().
+			Lines(Contains("file1")).
+			Press(keys.Universal.FocusMainView)
+
+		t.Views().Main().
+			IsFocused().
+			Press(keys.Universal.ToggleWhitespaceInDiffView)
+
+		t.Views().Files().
+			/* EXPECTED:
+			SelectionIsInactive()
+			ACTUAL: */
+			SelectionIsActive()
+	},
+})