When running the TreeView6 component in VB6's IDE, or using the OCX in an application that's in the IDE, it crashes. I have traced this to the IMalloc_ObjectFromPtr_PropertyGet method. The error seems to be that lPtr's value is 1, which is obviously an invalid pointer, but IMalloc tries to use it anyway.
It works fine compiled, as far as I can tell. The actual IDE crash doesn't seem to occur untiReplacing the line:
If Not (lPtr = 0) Then
in mIMalloc.bas with:
If (lPtr > 4) Or (lPtr <= -4) Then
Fixes the crashes for me. I'll leave it up to you to determine the real cause and actual problem resulting in this.