One minute my PHP/IDE was working find, the next minute I noticed there were no small blue dots in the margin showing which lines could be breakpointed. I must have inadvertently set/uset something. I have been through the View settings but couldn't see anything related there. Nor in Tools->Settings-Editor. I just know this is going to be like my trips to the supermarket where I ask an attendant where something is and they look at me pitifully, then point at the shelf I'm already looking at!

(Just in case it matters, I'm running under Windows 7 RC)

They appear in debug...

Out of curiosity, why aren't they there during regular editing?

Probably because the editor receives the "executable line"-information via the debugger when the code is actually being executed. The editor itself does have a parser for highlighting and so on, but I don't think it's advanced enough to determine all that while not running the actual code. As always, I'm trying to make an educated guess here, I have no idea on the actual inner workings of the editor and Dmitri might prove me wrong if he should answer