Require a ProjectWindow as ancestor of effect dialog...

... by passing parent as reference, not pointer, and testing in the dialog
factory function.

This is important so that we know the lifetime of an effect dialog, even when
it is non-modal, is bounded by the lifetime of the associated project.

src/effects/EffectUI.cpp

@@ -19,6 +19,7 @@
 #include "Effect.h"
 #include "EffectManager.h"
 #include "../ProjectHistory.h"
+#include "../ProjectWindowBase.h"
 #include "../TrackPanelAx.h"
 #include "RealtimeEffectManager.h"
 
@@ -377,7 +378,7 @@ void EffectRack::OnEditor(wxCommandEvent & evt)
    }
 
    auto pEffect = mEffects[index];
-   pEffect->ShowInterface( GetParent(), EffectUI::DialogFactory,
+   pEffect->ShowInterface( *GetParent(), EffectUI::DialogFactory,
       pEffect->IsBatchProcessing() );
 }
 
@@ -1812,15 +1813,22 @@ void EffectUIHost::CleanupRealtime()
    }
 }
 
-wxDialog *EffectUI::DialogFactory( wxWindow *parent, EffectHostInterface *pHost,
+wxDialog *EffectUI::DialogFactory( wxWindow &parent, EffectHostInterface *pHost,
    EffectUIClientInterface *client)
 {
    auto pEffect = dynamic_cast< Effect* >( pHost );
    if ( ! pEffect )
       return nullptr;
 
+   // Make sure there is an associated project, whose lifetime will
+   // govern the lifetime of the dialog, even when the dialog is
+   // non-modal, as for realtime effects
+   auto project = FindProjectFromWindow(&parent);
+   if ( !project )
+      return nullptr;
+
    Destroy_ptr<EffectUIHost> dlg{
-      safenew EffectUIHost{ parent, pEffect, client} };
+      safenew EffectUIHost{ &parent, pEffect, client} };
    
    if (dlg->Initialize())
    {
@@ -1913,7 +1921,7 @@ wxDialog *EffectUI::DialogFactory( wxWindow *parent, EffectHostInterface *pHost,
          EffectRack::Get( context.project ).Add(effect);
       }
 #endif
-      success = effect->DoEffect(&window,
+      success = effect->DoEffect(window,
          rate,
          &tracks,
          &trackFactory,