https://bugs.launchpad.net/ubuntu/+s…ty/+bug/160311

This bug is really annoying. Glad they’re working on it already. You can fix it yourself in the time being, like the instructions on the launchpad page state. If you’re not using Ambiance, change the path accordingly to the theme you’re using and edit the .xml file:

Workaround: Edit /usr/share/themes/Ambiance/metacity-1/metacity-theme-1.xml. Set the following values in frame_geometry_normal as desired:
<distance name=”left_width” value=”3″/>
<distance name=”right_width” value=”3″/>
<distance name=”bottom_height” value=”3″/>