I've been using PHPStorm for a month yet and it has been working great so far.
I'm not sure what I'm going to ask is possible but give it a try :) I moved my tabs to left side of IDE and see my opened files vertically. This is fine for me since I have a really wide screen. But, my screen is also a little bit higher in Y axis so there happens a big empty space below my opened tabs which are not more than 5-10. What I would like to do is place the Favourites window below to the panel that lists opened tabs, like you are able to do with other tool windows if you active Split mode on them.
I noticed that phpStorm does not assume tab list section as a tool window so it doesn't have an options menu to select Split Mode at the upper right corner.