Sometimes, during a debugging session, the ability to set breakpoints in Eclipse seems to break. From that moment onwards, double-clicking the margin no longer shows a blue ball, and neither does right clicking and explicitly asking to "toggle break point". This happens for all the lines.
- This happens rarely, but I already remember quite a few times it happened to me, on different machines, different operating systems and different Eclipse versions (3.6/3.7, maybe also 3.5)
- The file is saved and refreshed.
- This is a Java project in classic Eclipse.
- The line is a valid line for a breakpoint - in fact, once this happens, no line can get a breakpoint.
- Closing and re-opening the file, or restarting Eclipse, seems to solve the issue.
Because of the last bullet I'm pretty sure this is a bug of some sort. How can I avoid this behavior?