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IDProjectCategoryView StatusLast Update
0021562LazarusLCLpublic2020-02-12 22:42
ReporterRyan Davis Assigned To 
Status feedbackResolutionopen 
Product Version0.9.30.5 (SVN) 
Summary0021562: Bug in OnMouseMove X, Y values on Mac OS X
DescriptionWhen 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.
Additional InformationSee above.
TagsNo tags attached.
Fixed in Revision
Attached Files


Anton S.

2012-05-14 16:21

reporter   ~0059585

Last edited: 2012-05-14 16:27

I'v reported in 0020748 about an issue with drag from unfocused form, maybe it's in some way related.

Bart Broersma

2020-02-12 22:42

developer   ~0121066

Is this issue stll not resolved?
I guess it is in Carbon WS.
How does Cocoa WS behave?

Issue History

Date Modified Username Field Change
2012-03-26 10:36 Ryan Davis New Issue
2012-03-26 10:36 Ryan Davis Widgetset => Carbon
2012-05-14 16:21 Anton S. Note Added: 0059585
2012-05-14 16:27 Anton S. Note Edited: 0059585
2020-02-12 22:42 Bart Broersma Status new => feedback
2020-02-12 22:42 Bart Broersma LazTarget => -
2020-02-12 22:42 Bart Broersma Note Added: 0121066