For 4k monitors, check the Scale for the Windows Display settings. (Right-click the desktop and select "Display settings".)
It may be set at to high a value. (The default is 300%, which is crazy.) I've set it 125% on my 4k monitor and that works fine.
Ironically, things may now be too small.
To fix that, Right-click the iClone desktop icon and select Properties and then click the Compatibility tab. Once there, click Change high DPI settings.
At the pop-up that opens, go to the High DPI scaling override, click the check mark and select System (Enhanced) from the drop-down.
76% of original size (was 659x19) - Click to enlarge