Drag and drop of alignment file onto alignment window not working correctly when in a HiDPI scaled mode in Linux

When Jalview runs in a HiDPI upscaled mode, dragging and dropping an alignment file onto an existing alignment window seems to expect the alignment window in a size and position as if no upscaling had been applied.
This means the alignment file will most often appear in a new alignment window when it looks like it was dropped onto an existing one, and can be appended to an existing alignment window when it looks like it should open a new one.
It looks like the calculation for when dropping a file onto an existing window needs to know about the scaling factor being applied. This will only be happening in Linux since the HiDPI upscaling for Windows and macOS are already dealt with by the JRE and OS (though this will be tested).