README update

README.md

@@ -199,6 +199,17 @@ $ cd analyzer
 $ ./traceAnalyzer
 ```
 
+Note for GNU/Linux users:
+
+If your keyboard shortcuts (e.g., Ctrl+O, Ctrl+T) from the traceAnalyzer menu
+appear as "ghost" and pressing any of the key combinations has no effect then
+you may need to set an extra environment variable:
+
+``` bash
+$ export QT_QPA_PLATFORMTHEME=qgnomeplatform
+$ ./traceAnalyzer
+```
+
 ### Building on OSX
 
 - Install SystemC in /opt (as usual with ./configure --prefix=/opt/systemc; make; make install;).