I guess you don't want to upgrade ubuntu?
You could try turning off auto-reload, see if it helps.
Also try turning off the file tabs toolbar - it has some performance issues.
Or you could run slick from a brand new config folder using the -sc switch when you invoke slick
vs.exe +new -sc some-new-empty-folder
see if you still get the problem, if not try exporting your configuration from your normal config folder and importing to the new one. (Or just rename vslick.stu to vslick.stu.old then run slick and force it to make a new one).
Or, look up "profiling" in the slick c help file index. On the command line you can activate profiling by typing profile on/off.
If you want you could try the following code to automatically activate profiling when slick gets the focus, but my guess is the profiling won't start in time to be useful so maybe you could change the code to turn profiling on when slick loses the focus (i.e. change to if(!gettingFocus).
Functions whose name starts with _actapp_ get called when slick loses or gains the focus. To use the code, create a new file say mytest.e in your config folder, add the following and load it using the load module command on the macro menu.
#include "slick.sh"
#pragma option(strictsemicolons,on)
#pragma option(strict,on)
#pragma option(autodecl,off)
#pragma option(strictparens,on)
void _actapp_too_slow(_str gettingFocus)
{
if (gettingFocus) {
profile("on");
}
}