In Eclipse, why does "Build Automatically" get mysteriously disabled?

Question

I'm running Eclipse Europa (3.3). I leave the "Build Automatically" setting, under the Project menu, on all the time. Once in awhile my code isn't compiling, and I puzzle over it and then pull down the Project menu ... lo and behold, it's not set anymore. What gives? Is this a bug, or is there something else I'm doing that could cause it?

Edit: I am running the regular Java developer installation, plus Subversive and its connectors, Jetty Launcher, and I believe no other plugins. Other people at my workplace have had the same problem.

Edit: I am still having this problem once in a blue moon, only now I'm using Eclipse Galileo (3.5) for Windows. I haven't had this problem in Galileo for OS X, neither in Cocoa nor Carbon, but I have not used that for as long.

Answer 1

With Eclipise Mars.1 (4.5.1), Oomph may be the culprit. Eclipse Oomph supports automatically disabling Build Automatically with entries in

On Windows %USERPROFILE%\.eclipse\org.eclipse.oomph.setup\setups\user.setup

If you want to disable this Oomph behavior try deleting the following setting

"Eclipse->Navigate Menu-> Open Setup menu entry-> Open User menu entry", a Preference Task under "User Preferences -> org.eclipse.core.resources -> description.autobuilding"

I learned about this setting by posting to the Oomph Eclipse Community Forum on Feb 8th, 2016. I posted a question titled "Oomph Defect? Build Automatically Keeps Getting Disabled". Ed Marks replied the same day with details about Oomph's support for managing the Eclipse "Build Automatically" setting. https://www.eclipse.org/forums/index.php/m/1722751/#msg_1722751