I've been able to reproduce systematically a problem that's related to the HintTimer in uniteditor.pp. Apparently Shane has also tried to hunt this down?

The problem appears when I move the mouse over the sourcenotebook while Lazarus starts. The mousemoves fire events at TSourceNotebook.EditorMouseMove where FHintTimer is disabled and enabled again to reset the delay before showing a hint.

Here's where it gets interesting. Just add a "var a: Integer;" and nothing else to TSourceNotebook.EditorMouseMove and it doesn't crash any more. This is with fpc-1.0.5-laz.20010815

I then added a global integer and increased it after every FHintTimer:=false in EditorMouseMove. It runs 3-7 times before it hanging. The timer itself doesn't hang though. Just the notebook form.

/jarto