I encountered this problem also, I went with the second answer, however, I only removed /.metadata/.plugins/org.eclipse.core.runtime/.settings - this way I was able to preserve my workspace settings (source code etc)
Going forward I would recommend downloading the Eclipise Color Theme Plugin from http://www.eclipsecolorthemes.org/ - This allows you to switch between a range of color themes easily, and easily switch back to 'Default'