I have been having the same problem. It is a windows 10 compatibility issue. Qlik has not addressed this but must quickly - you can't even see the icons they are so small. funny the book mark tool bar has bigger text - but it is so small (width) you can't read the book mark names. this is not something all the users can solve with an extension. Qlik needs to put the smartest people they have on this as it is going to lower the overall satisfaction rating from their users. We are on V11xx will be moving to 12 so it is just not a qlikview 12 issue - it is in the core Qlik software.
I believe microsoft deals with this with a manifest file.
qlik needs to do something.
For Now: This is a DPI scaling issue. Most software was designed in lower resolution so all the icons for the tool bars are tiny in the new HD resolution hardware. I have this experience with alot of software I use. This is my work around:
In the windows10 search box type the name of your software, right click on the search result, then choose select Open file location. Right click on that file select Properties; select the compatibility tab, in the settings group check override high DPI scaling behavior. Then inside the software when you open it everything will seem really big, so go to your view \ zoom setting and select like 75%. Note the tool bars and icons are the normal 100% while the program info will be at 75% and everything will look way better.
It is a work around at best, but better than not being able to see any of the icons on the tool bars at all!