Fixed an assert when calling CloseCurrentPopup() twice in a row.

imgui.cpp

@@ -3495,7 +3495,7 @@ void ImGui::CloseCurrentPopup()
 {
     ImGuiContext& g = *GImGui;
     int popup_idx = g.CurrentPopupStack.Size - 1;
-    if (popup_idx < 0 || popup_idx > g.OpenPopupStack.Size || g.CurrentPopupStack[popup_idx].PopupId != g.OpenPopupStack[popup_idx].PopupId)
+    if (popup_idx < 0 || popup_idx >= g.OpenPopupStack.Size || g.CurrentPopupStack[popup_idx].PopupId != g.OpenPopupStack[popup_idx].PopupId)
         return;
     while (popup_idx > 0 && g.OpenPopupStack[popup_idx].Window && (g.OpenPopupStack[popup_idx].Window->Flags & ImGuiWindowFlags_ChildMenu))
         popup_idx--;
@@ -3549,7 +3549,6 @@ bool ImGui::BeginPopup(const char* str_id)
     return BeginPopupEx(g.CurrentWindow->GetID(str_id), ImGuiWindowFlags_ShowBorders);
 }
 
-// FIXME
 bool ImGui::IsPopupOpen(ImGuiID id)
 {
     ImGuiContext& g = *GImGui;