Random errors: what can cause them

Missing iEndPrinting:
When you use some direct printing instructions in your code, like iCreateFont or iFont, and then forget the iEndPrinting, you have a beautiful case of problem depending of the operating system and perhaps also of the printer driver (I saw that one only in WinDev 5.5, by the way)... Under some OS/printer combination, you will have a crash the next time you do a iCreateFont/iFont in another process.

It looks like this is another case of internal pointers being messed up (in that case not reset by the iEndPrinting)...

The problem is simple enough, finding it can be more tricky :-(