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I'm writing a component that will allow the user to "snap" a window to
the side of an MDI window, which will create a panel that will
represent the auto-hide window. The problem is, no matter what I do
to try and store a pointer to the form in my TDockingPanel class, I
get an access violation when attempting to access it from within the
class. However, when I access the pointer from outside the class, I
get no access violation, and everything is correct! Here's the code:

class PACKAGE TDockingPanel : public TPaintBox
{
private:
TNotifyEvent FOnMouseEnter;
TNotifyEvent FOnMouseLeave;
AnsiString FCaption;
bool MouseIsOver;
bool Down;
TTimer *Timer;
AnsiString FPanelForm;
void __fastcall CustomPaint(TObject *Sender);
void __fastcall ClickEvent(TObject *Sender);
void __fastcall TimerEvent(TObject *Sender);
void __fastcall MouseEnter(TObject *Sender);
void __fastcall MouseLeave(TObject *Sender);
void __fastcall WriteCaption(AnsiString c);
void __fastcall GrowRect(TRect &R, int pixels);
HFONT __fastcall CreateVerticalFont();
void __fastcall CenterText(AnsiString text);
void __fastcall RevealForm();
void __fastcall HideForm();
protected:
void __fastcall WndProc(TMessage &Message);
public:
__fastcall TDockingPanel(TComponent* Owner);
TForm *f; // the form associated with this TDockingPanel
__published:
__property AnsiString Caption = {read = FCaption, write =
WriteCaption};
__property TNotifyEvent OnMouseEnter = {read = FOnMouseEnter,
write = FOnMouseEnter};
__property TNotifyEvent OnMouseLeave = {read = FOnMouseLeave,
write = FOnMouseLeave};
};

// an example member function which gives an access violation:

void __fastcall TDockingPanel::RevealForm()
{
if (f)
{
ShowMessage(f->Caption);
}
}

// a simplified example which does NOT give an access violation

void __fastcall TForm2::Start1Click(TObject *Sender)
{
DockingPanel1->f = Form1;
ShowMessage(DockingPanel1->f->Caption);
}

How could this be? I'm using BCB 5. The component is included in
package dclusr50. It doesn't make much sense. By the way,
TDockingPanel::RevealForm() is generated on a MouseEnter event, which
I trigger AFTER the form's address has been assigned to f. CodeGuard
says I have an access overrun in Start1Click. I don't know what this
means or how to fix it. I've tried making f a property of
TDockingPanel, but that didn't work either.

TIA.