Using 6.4.4.2 now in a laptop with touchpad and an external mouse together.
10JUN2020, right after updating windows10 to a new build, a terrible error occurred while using Calc.
As fast scrolling with mouse wheel or touchpad, the page move suddenly stops and can pick/enter any cell in the spreadsheet. When locate mouse pointer on the rolldown menu, there comes an empty grey box. This happens the same when trying to close the file with x mark on the right upperside corner if the sheet has been modified with new input.
Even when re-opening the file, quite frequently, there comes only the top band of “filename-LibreOffice Calc” with empty screen below the bar.
Meanwhile, such scrolling won’t cause any trouble with various browsers or any O/S related configuration screens.
Hope I could get a solution for this shortly. Thanks.