Title of inactive panes is not visible with the Windows Classic theme

[didierbr]

When using a Windows Classic theme under Windows 7, the title of inactive panes is not visible, because the colour of the title is the same as the colour of the background.

We created a workaround, by using lighter/darker colours when they are the same: https://sourceforge.net/p/omegat/svn/6534/tree//trunk/src/org/omegat/util/gui/DockingUI.java?diff=5161c5ece88f3d0a5207336e:6533

Didier