We get an assertion when entering DOM full-screen mode:
###!!! ASSERTION: Non-zero percentage values not currently supported: 'minWidth.GetPercentValue() == 0.0f', file /home/cpearce/src/m-c/layout/xul/base/src/nsBox.cpp, line 771
Something in the "Press ESC to exit full-screen mode" warning is using a non-zero min-width, causing this.
Created attachment 573727 [details] [diff] [review]