[Closed] [SDK] Crash after object creation

Hey,

I have a strange problem with a crash after creating an object with a plugin utility.
Either I have a mistake in the code or understanding how max generates an object, or there is a bug in Max. I tend to option one.
The base code was created with the max-wizard in Visual Studio 2010 for Max 2014.

Here the code of the plugin.cpp:

#include "bakePlugin.h"
#include "bakeUtil.h"

#define bakePlugin_CLASS_ID	Class_ID(0x6d6dfd1f, 0x94871f48)

class bakePlugin : public UtilityObj 
{
public:
		
	//Constructor/Destructor
	bakePlugin();
	virtual ~bakePlugin();

	virtual void DeleteThis() { }
	
	virtual void BeginEditParams(Interface *ip, IUtil *iu);
	virtual void EndEditParams(Interface *ip, IUtil *iu);

	virtual void SelectionSetChanged(Interface *ip, IUtil *iu);

	virtual void Init(HWND hWnd);
	virtual void Destroy(HWND hWnd);
	
	// Singleton access
	static bakePlugin* GetInstance() { 
		static bakePlugin thebakePlugin;
		return &thebakePlugin; 
	}

private:

	static INT_PTR CALLBACK DlgProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);

	HWND   hPanel;
	IUtil* iu;
	Interface* ip;

	ICustButton *applyButton;
	
};


class bakePluginClassDesc : public ClassDesc2 
{
public:
	virtual int IsPublic() 							{ return TRUE; }
	virtual void* Create(BOOL /*loading = FALSE*/) 	{ return bakePlugin::GetInstance(); }
	virtual const TCHAR *	ClassName() 			{ return GetString(IDS_CLASS_NAME); }
	virtual SClass_ID SuperClassID() 				{ return UTILITY_CLASS_ID; }
	virtual Class_ID ClassID() 						{ return bakePlugin_CLASS_ID; }
	virtual const TCHAR* Category() 				{ return GetString(IDS_CATEGORY); }

	virtual const TCHAR* InternalName() 			{ return _T("bakePlugin"); }	// returns fixed parsable name (scripter-visible name)
	virtual HINSTANCE HInstance() 					{ return hInstance; }					// returns owning module handle

};


ClassDesc2* GetbakePluginDesc() { 
	static bakePluginClassDesc bakePluginDesc;
	return &bakePluginDesc; 
}


//--- bakePlugin -------------------------------------------------------
bakePlugin::bakePlugin()
	: hPanel(nullptr)
	, iu(nullptr)
{
	
}

bakePlugin::~bakePlugin()
{

}


void bakePlugin::BeginEditParams(Interface* ip, IUtil* iu) 
{
	this->iu = iu;
	hPanel = ip->AddRollupPage(
		hInstance,
		MAKEINTRESOURCE(IDD_PANEL),
		DlgProc,
		GetString(IDS_PARAMS),
		0);

	GenBoxObject* geoObj = (GenBoxObject*)ip->CreateInstance(GEOMOBJECT_CLASS_ID, Class_ID(BOXOBJ_CLASS_ID, 0));

	geoObj->SetParams(1.0f, 1.0f, 1.0f, 1, 1, 1, FALSE);

	INode *boxNode = ip->CreateObjectNode(geoObj);
	
}
	
void bakePlugin::EndEditParams(Interface* ip,IUtil* iu)
{
	this->iu = nullptr;
	this->ip = nullptr;

	ip->DeleteRollupPage(hPanel);

	hPanel = nullptr;
}

void bakePlugin::SelectionSetChanged(Interface *ip, IUtil *iu)
{

}

void bakePlugin::Init(HWND hWnd)
{
	applyButton = GetICustButton(hWnd);
}

void bakePlugin::Destroy(HWND hWnd)
{
	//ReleaseICustButton(applyButton);
}

INT_PTR CALLBACK bakePlugin::DlgProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
	switch (msg) 
	{
		case WM_INITDIALOG:
			bakePlugin::GetInstance()->Init(hWnd);


			break;

		case WM_DESTROY:
			bakePlugin::GetInstance()->Destroy(hWnd);
			break;

		case WM_COMMAND:
			switch(LOWORD(wParam))
			{
				case IDC_APPLYBUTTON:

					break;

				default:

					break;
			}
			
			break;

		case WM_LBUTTONDOWN:
		case WM_LBUTTONUP:
		case WM_MOUSEMOVE:
			GetCOREInterface()->RollupMouseMessage(hWnd,msg,wParam,lParam);
			break;

		default:
			return 0;
	}
	return 1;
}

The code is compiled and executed in Max. The object is also visible in the viewport, but when I try to select the object or select it in the object list, Max crashes.

Unhandled exception at 0x365411f6 (bakePlugin.dlu) in 3dsmax.exe: 0xC0000005: Access violation reading location 0x0000000000000000.

The location of the variable already seems to be wrong (0x0000000000000000). But is there any wrong initialized variable?

Thanks for your help,
Florian