Trouble capturing events in a popup menu

I have a general-purpose popup menu for grid controls that is part of the form template.
It has 3 items Add, Edit, and Delete, and these are all Enabled and Visible in the form template.
When it works, it does exactly what I want it to do.

The problem is that is doesn't always work: it appears to get "stuck" and any events I try to apply to it get queued up as though they belong to the grid control underneath.

During debugging I notice that the call to ATGUISHOW for the popup happens, but the subsequent PRINT statement isn't executed until after I click elsewhere (or when the popup menu responds to the event).

Can anybody help?  Has anyone run into anything like this?

This is the routine I'm using to invoke the popup menu - several of my grid GECONTEXT event handlers simply do a GOTO here:
<------------------------------>
GRID.CONTEXT:
  ROW = GUIARGS<1,2>
  CALL ATGUISETPROP(GUIAPP,GUIFRM,GUICTL,GPROW,0,0,ROW,GUIERRORS,GUISTATE)
  IF ROW NE 0 THEN
    ACTIVE.GRID = GUICTL
    CTL = "menuGrids"
    IF ROW EQ -1 THEN
      SHOW.ADD = "ATGUISHOW"
      SHOW.CHG = "ATGUIHIDE"
      SHOW.DEL = "ATGUIHIDE"
    END ELSE
      SHOW.ADD = "ATGUIHIDE"
      SHOW.CHG = "ATGUISHOW"
      SHOW.DEL = "ATGUISHOW"
    END
    CALL @SHOW.ADD(GUIAPP,GUIFRM,CTL,"ADD",GUIERRORS,GUISTATE)
    CALL @SHOW.CHG(GUIAPP,GUIFRM,CTL,"EDIT",GUIERRORS,GUISTATE)
    CALL @SHOW.DEL(GUIAPP,GUIFRM,CTL,"DELETE",GUIERRORS,GUISTATE)
    CALL ATGUISHOW(GUIAPP,GUIFRM,CTL,'',GUIERRORS,GUISTATE)
    PRINT ACTIVE.GRID
  END
  RETURN