Draw embedded views as one focused unit

A view can only be drawn with the focused frame and title colors while it
is the current view, but a panel made of an outer view and an editable
field embedded in it has to look focused as a whole, whichever of the two
the keyboard is pointed at.

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

pkg/gocui/gui.go

@@ -1615,6 +1615,20 @@ func (g *Gui) ForceFlushViewsContentOnly(views []*View) error {
 	return g.flushContentOnly(views)
 }
 
+// hasFocus reports whether a view is drawn as focused. Views that are embedded
+// in one another (see View.ParentView) form a single unit, so they are all drawn
+// as focused while any one of them is the current view.
+func (g *Gui) hasFocus(v *View) bool {
+	return g.currentView != nil && outermostView(v) == outermostView(g.currentView)
+}
+
+func outermostView(v *View) *View {
+	for v.ParentView != nil {
+		v = v.ParentView
+	}
+	return v
+}
+
 // draw manages the cursor and calls the draw function of a view.
 func (g *Gui) draw(v *View) error {
 	if !v.Visible || v.y1 < v.y0 || v.x1 < v.x0 {
@@ -1639,7 +1653,7 @@ func (g *Gui) draw(v *View) error {
 
 	if v.Frame {
 		var fgColor, bgColor, frameColor Attribute
-		if g.Highlight && v == g.currentView && g.IsFocused() {
+		if g.Highlight && g.hasFocus(v) && g.IsFocused() {
 			fgColor = g.SelFgColor
 			bgColor = g.SelBgColor
 			frameColor = g.SelFrameColor

pkg/gocui/parent_view_test.go

@@ -56,6 +56,26 @@ func TestFirstMatchingKeybindingOfParentViewWins(t *testing.T) {
 	assert.Equal(t, []string{"first"}, pressed)
 }
 
+func TestEmbeddedViewsAreFocusedTogether(t *testing.T) {
+	g := newTestGui(t)
+	parent, child := setupParentAndChildView(t, g)
+	sibling, _ := g.SetView("sibling", 0, 12, 20, 14, 0)
+	sibling.ParentView = parent
+	unrelated, _ := g.SetView("unrelated", 30, 0, 50, 10, 0)
+
+	assert.True(t, g.hasFocus(child))
+	assert.True(t, g.hasFocus(parent))
+	assert.True(t, g.hasFocus(sibling))
+	assert.False(t, g.hasFocus(unrelated))
+
+	_, err := g.SetCurrentView(unrelated.Name())
+	assert.NoError(t, err)
+
+	assert.True(t, g.hasFocus(unrelated))
+	assert.False(t, g.hasFocus(parent))
+	assert.False(t, g.hasFocus(child))
+}
+
 func TestPrintableKeysGoToTheFieldBeingTypedIn(t *testing.T) {
 	for _, test := range []struct {
 		name              string

pkg/gocui/view.go

@@ -210,7 +210,9 @@ type View struct {
 	// Overlaps describes which edges are overlapping with another view's edges
 	Overlaps byte
 
-	// ParentView is the view which catches events bubbled up from the given view if there's no matching handler
+	// ParentView is the view which catches events bubbled up from the given view if there's no matching handler.
+	// Views related this way are also drawn as a single focused unit: while one of
+	// them is the current view, they all get the focused frame and title colors.
 	ParentView *View
 
 	searcher *searcher