I\'m working on an Eclipse plugin that needs to change some preferences defined by other plugins, e.g. the tab size in text editors. Is that possible?
Yes, it is possible.
You'll need this in your preference page:
setPreferenceStore( new ScopedPreferenceStore( new InstanceScope(), "bundle-name-of-other-plugin" ) );
Or you could do something like this here.
FYI, the preferences live here:
pathToWorkspace\.metadata\.plugins\org.eclipse.core.runtime\.settings