This is likely to be related to the theme. Geany does not specify what an active tab looks like (see [geany.css](https://github.com/geany/geany/blob/master/data/geany.css)), so whatever the theme defines will be used.
On my Mint (Ubuntu based) system with GTK 3.18.9, the active tab is clearly defined with an out-of-the-box Geany. --- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://github.com/geany/geany/issues/1156#issuecomment-236423367
