1. What is your Pinta version from Help | About menu?
2. What is your operating system name and version?
3. Is this the only application you have a problem with this kind of displaying?
It looks to me like some kind of graphic driver problem or something like that. Can you check your graphic driver and update it if appropriate.
Due to how old this issue is and how many system configurations I changed, it's unlikely I can reproduce it again. I'd suggest closing this one for good.
1. What is your Pinta version from Help | About menu?
2. What is your operating system name and version?
3. Is this the only application you have a problem with this kind of displaying?
It looks to me like some kind of graphic driver problem or something like that. Can you check your graphic driver and update it if appropriate.