Drag and drop support in plugin

Hello,

I was going through Panelator sample plugin code and saw that they are creating dockable panel using OS Controls. I was just trying to check if i can add code for handling any drag and drop on that panel. So i modified the code in that like this..

PanelatorUI_Plat::PanelatorUI_Plat(SPBasicSuite* spbP, AEGP_PanelH panelH,
                            AEGP_PlatformViewRef platformWindowRef,
                            AEGP_PanelFunctions1* outFunctionTable) : PanelatorUI( spbP, panelH, platformWindowRef, outFunctionTable)
{

    WindowRef hostWindow;
   
    hostWindow = (WindowRef) HIViewGetWindow(platformWindowRef);
   
    Boolean t = true;
    OSStatus status = SetAutomaticControlDragTrackingEnabledForWindow(hostWindow, t);
    static const EventTypeSpec  kDrawEventSpec[] = {    { kEventClassControl,  kEventControlDraw },
                                                        { kEventClassControl, kEventControlDragEnter },
                                                        { kEventClassControl, kEventControlDragWithin },
                                                        { kEventClassControl, kEventControlDragLeave },
                                                        { kEventClassControl, kEventControlDragReceive }
                                                    };
       OSErr    err = InstallEventHandler (GetControlEventTarget ( i_refH), // 6
                                        NewEventHandlerUPP (S_EventHandler),
                                        5,
                                        kDrawEventSpec,
                                        (void *) this,
                                        NULL);

}

and in the EventHandler func i'm checking if the eventKind is kEventControlDragEnter. My problem is what ever component i drag on the panel, it is not sending kEventControlDragEnter event to EventHandler func. Can please anyone tell me why it control doesn't come to EventHandler func.