On 16 Sep 2014, at 16:05, Caio Fernando Bertoldi Paes de Andrade wrote:
[…] I thought of having transparency only in the File Browser, like a sidebar app
This is what Apple is suggesting, though only for source lists. TextMate’s file browser isn’t a source list, but for people who prefer this look, it can be made to use the style by running:
defaults write com.macromates.TextMate.preview fileBrowserStyle SourceList
I believe that should give a blurred transparent background on Yosemite.