4K Display Symbols realy small

Hallo

I got a 4K display on my ne laptop. Although I increased the zoom factor up to 250% the Lightroom signs (for example the lock) are unbeklievable small, so I have to come really close to find them. I´ve allready looked trough the settings but find no option to configure the symbol size.

Does anyone know how to get the signs readable?

Thanks for your support!

Lightroom Version 2015.13