|Description||When tracking X or Y values in OnMouseMove they consistently go negative when moving outside the range of a component. For example, if you tracked the X value in OnMouseMove of a TImage, when moving the mouse to the left of the TImage the X value would go negative as the cursor exited the TImage. This is often a useful value to track for implementing the start of drag/drop procedures.|
This works normally in Windows for all cases. E.g. the X or Y value will go negative while exiting a component.
This works normally in Mac for a standard window which has focus and working within a single focused window.
If working with two Windows on the Mac, the X value in OnMouseMove will not go negative when exiting the visual component space if the Window in which you are exiting did not have focus when you begin the move operation. For example, if you try to drag back and forth between two windows using OnMouseMove negative values to detect when to begin dragging, the procedure will work for whatever window currently has focus. However, if you try to drag from the window without focus (which instantly gives it focus when you click on it) to the original window the X, Y values in OnMouseMove will never go negative.
The exact same code in Windows when using two windows works fine.