Please post a small project which shows the issue - without seeing any code it is very difficult to help.Done.
Well, Lazarus itself is a high-DPI application, and AFAIK it does not need such tricks. So I guess you are doing something in a way which is not correct for the LCL scaling.But not on Win10 (with latest HighDPI or Per monitor, or changing dpi without logout (V2)).
For left and right you can use:Hello ps, thanks for this example code, I will try it !
Self.SetBounds(Screen.Width - MulDiv(Self.Width, Self.Monitor.PixelsPerInch, 96), 0, Self.Width, R.Bottom );