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IDProjectCategoryView StatusLast Update
0005297JEDI VCL00 JVCL Componentspublic2012-02-29 16:55
ReporterKiriakosAssigned ToAHUser 
Status resolvedResolutionfixed 
Product VersionDaily / GIT 
Target VersionFixed in Version3.45 
Summary0005297: JvDocking Floating form not drawing correctly
DescriptionDocking style VSNet
When I drag form from a docked state to a floating state *sometimes* it is not painted correctly.
Additional InformationFix:
In JvDockSupportForm procedure DoFloatForm insert one line:

  procedure DoFloatForm(Control: TControl);
    WasVisible: Boolean;
    if Control.FloatingDockSiteClass = Control.ClassType then
      WasVisible := Control.Visible;
        DragObject.AlphaBlendedForm.Hide; // line inserted
        Control.Dock(nil, DragObject.DockRect);
        if (Control.Left <> DragObject.DockRect.Left) or (Control.Top <> DragObject.DockRect.Top) then
          Control.Left := DragObject.DockRect.Left;
          Control.Top := DragObject.DockRect.Top;
        if WasVisible then

This extra line hides the alpha blended form before showing the floating form.

Also while we are at it there is absolutely no reason for TJvAlphaBlendedForm to inherit from TJvForm.
TagsNo tags attached.



2010-08-20 11:49

administrator   ~0017606

Please provide the zipped sources of a sample application showing this


2010-08-30 04:55

reporter   ~0017629

I had this problem with PyScripter (sources at and it would be hard to reproduce in a simple example.

However, if you see what the change is doing it is hiding the AlphaBlended form used while dragging forms, before making visible the dragged form. This is good practice anyway and cannot do any harm. In the problem I had, when the AlphaBlended form was hidden/destroyed it messed up the appearance of the already shown dragged form for some unknown reason.

By the way I am the contributor of the AlphaBlended stuff.


2010-09-16 22:31

reporter   ~0017683

Actually the problem is reproducible with the DockingInCode JvDocking demo in Windows 7.

- Run the demo.
- Press the Conjoined dock button.
- Drag a form to a floating position.

The form is not painted properly.


2010-10-11 10:12

administrator   ~0017863

Someone with Win7 will have to look at this, provided it is not already fixed in SVN


2010-11-28 15:26

developer   ~0018216

Fixed in svn revision 12934.

Issue History

Date Modified Username Field Change
2010-08-14 04:33 Kiriakos New Issue
2010-08-20 11:49 obones Note Added: 0017606
2010-08-20 11:49 obones Status new => feedback
2010-08-30 04:55 Kiriakos Note Added: 0017629
2010-09-16 22:31 Kiriakos Note Added: 0017683
2010-10-11 10:12 obones Note Added: 0017863
2010-10-11 10:12 obones Status feedback => acknowledged
2010-11-28 15:26 AHUser Note Added: 0018216
2010-11-28 15:26 AHUser Status acknowledged => resolved
2010-11-28 15:26 AHUser Fixed in Version => Daily / SVN
2010-11-28 15:26 AHUser Resolution open => fixed
2010-11-28 15:26 AHUser Assigned To => AHUser
2012-02-29 16:55 obones Fixed in Version Daily / SVN => 3.45