Issue with PF_Cmd_DO_DIALOG on macOS

I have implemented a popup on PF_Cmd_DO_DIALOG in both macOS and Windows.

The popup for macOS works well in a test program outside AE. On AE, most of the window appears grayed out.

Using Xcode, I got the following trace. Any ideas how this can be fixed or avoided ?

2021-07-18 03:43:03.729883+0530 After Effects[1421:57106] [com.adobe.AfterEffects] CGBitmapContextGetWidth: invalid context 0x600003722340. Backtrace:
  <CGBitmapContextGetWidth+49>
   <-[FLView create_aux_bitmap:retina:]+55>
    <-[FLView drawRect:]+360>
     <_NSViewDrawRect+139>
      <-[NSView _drawRect:clip:]+1103>
       <-[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:]+2143>
        <-[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:]+3503>
         <-[NSView _oldDisplayRectIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:]+2126>
          <-[NSView displayIfNeeded]+755>
           <-[NSWindow displayIfNeeded]+261>
            <__NSWindowGetDisplayCycleObserverForDisplay_block_invoke+646>
             <NSDisplayCycleObserverInvoke+155>
              <NSDisplayCycleFlush+937>
               <_ZN2CA11Transaction19run_commit_handlersE18CATransactionPhase+106>
                <_ZN2CA11Transaction6commitEv+230>
                 <__62+[CATransaction(NSCATransaction) NS_setFlushesWithDisplayLink]_block_invoke+266>
                  <___NSRunLoopObserverCreateWithHandler_block_invoke+41>
                   <__CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__+23>
                    <__CFRunLoopDoObservers+457>
                     <__CFRunLoopRun+874>
                      <CFRunLoopRunSpecific+462>
                       <RunCurrentEventLoopInMode+292>
                        <ReceiveNextEventCommon+359>
                         <_BlockUntilNextEventMatchingListInModeWithFilter+64>
                          <_DPSNextEvent+883>
                           <-[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:]+1352>
                            <_ZN22Fl_Cocoa_Screen_Driver4waitEd+504>
                             <_ZN2Fl3runEv+44>
                              <_ZL8RegisterP9PF_InDataP10PF_OutData+136>
                               <EntryPointFunc+1557>