First, great release, thank you very much!

I use two ways to change the volume, either by using the volume keys on my keyboard or by using the mouse wheel when the mouse is over the system tray icon of kmix.
Both ways used to change the volume by 5% up until version 4.3. Now I have seen, that it can be configured in the config file but is set to 5% by default. That works fine when using the keyboard but using the mouse wheel will change the volume by 15% which is way too much.

Reproducible: Always

Steps to Reproduce:
1. Change the volume with the keyboard
2. Watch the amount of volume changed
3. Change the volume with the mouse wheel, the mouse pointer being on top of the system tray icon
4. Watch the amount of volume changed
Actual Results:  
Changing via keyboard changes the volume by 5%.
Changing via mouse wheel changes the volume by 15%.

Expected Results:  
Both ways the volume should be changed by 5%.

I'm using pulse audio, the main channel in kmix is set to the playback device I'm using (Internal Audio Analogue Stereo).