Fix sidebar repaint and command restart navigation

internal/app/viewport_renderer_test.go

@@ -211,6 +211,34 @@ func TestViewportRendererFlagsScrollVerbs(t *testing.T) {
 	}
 }
 
+func TestViewportRendererFlagsLineFeedAtViewportBottomAsScrolling(t *testing.T) {
+	vr := newViewportRenderer(newTerminalLayout(120, 40))
+	_ = vr.Render([]byte("\x1b[37;1H\n"))
+	if !vr.TookScrollAction() {
+		t.Fatalf("LF at viewport bottom should flag scroll")
+	}
+}
+
+func TestViewportRendererDoesNotFlagLineFeedBeforeViewportBottom(t *testing.T) {
+	vr := newViewportRenderer(newTerminalLayout(120, 40))
+	_ = vr.Render([]byte("\x1b[36;1H\n"))
+	if vr.TookScrollAction() {
+		t.Fatalf("LF before viewport bottom should not flag scroll")
+	}
+}
+
+func TestViewportRendererFlagsLineFeedAtCustomScrollBottom(t *testing.T) {
+	vr := newViewportRenderer(newTerminalLayout(120, 40))
+	_ = vr.Render([]byte("\x1b[5;10r\x1b[9;1H\n"))
+	if vr.TookScrollAction() {
+		t.Fatalf("LF before custom scroll bottom should not flag scroll")
+	}
+	_ = vr.Render([]byte("\n"))
+	if !vr.TookScrollAction() {
+		t.Fatalf("LF at custom scroll bottom should flag scroll")
+	}
+}
+
 func TestViewportRendererForwardsRIVerbatim(t *testing.T) {
 	// We rely on the host terminal performing the scroll inside the
 	// DECSTBM region; the renderer must not eat or transform RI. If a