IDE 1.5.5 and OSX 10.9.2 : OSX crash!

This one is intermittent, but easy to repro.

Repro steps: 1- Load any program (even "blink" can cause this) 2-Modify program 3-Upload the program 4-If it works, goto step 2

Result: After a few tries (sometimes about 10), OSX itself will crash before the upload stage is completed, and you'll have to reboot the mac.

Note: This happened to me even when I inadvertently forgot to plug the board via USB.

Needless to say, this is quite a showstopper, as crashing a Unix-like system isn't exactly recommended...

I had the same problem. I also had trouble with the hesitant scrolling of the editing window.
I made the change to and now use Xcode. Works well for me.