fix(ui): Prevent PopStyleColor crash by using frame-scoped tint flag

src/gui_2.py

@@ -256,9 +256,11 @@ class App:
    imgui.end_menu()
 
  def _gui_func(self) -> None:
+  pushed_prior_tint = False
   if self.perf_profiling_enabled: self.perf_monitor.start_component("_gui_func")
   if self.is_viewing_prior_session:
    imgui.push_style_color(imgui.Col_.window_bg, vec4(50, 40, 20))
+   pushed_prior_tint = True
   try:
    self.perf_monitor.start_frame()
    self._autofocus_response_tab = self.controller._autofocus_response_tab
@@ -761,7 +763,7 @@ class App:
    import traceback
    traceback.print_exc()
   
-  if self.is_viewing_prior_session:
+  if pushed_prior_tint:
    imgui.pop_style_color()
   
   if self.perf_profiling_enabled: self.perf_monitor.end_component("_gui_func")