There’s an ongoing bug report about this. It’s actually two issues that are combined because the white dot issue affects (in some cases, not always) mouse interaction with cockpit buttons, switches and knobs.
The bug report is here, and the thread about the white dot is here (I’m almost sure there was another bug report for the white dot alone, but can’t find it)
Unfortunately there’s no hot fix for this, and if I recall correctly it’s scheduled for the next or the following SU.