Now that I've improved the handling of splitters in a dock site, I again
came across some weird behaviour of the LCL, depending on the widgetset :-(
To reproduce:
1. Run examples/dockmanager/easytree/easydocking.
2. Dock one or more controls into the dock site.
3. Press (and hold) the left mouse button over the dockzone header of a
docked control.
4. Move the mouse around.
Now you'll find the control (associated with the header) being dragged
with the gtk2 widgetset, but with the win32 widgetset nothing will
happen at all, and the whole application becomes unresponsive :-(
Can somebody explain what will happen when the mouse is pressed over one
control (or menu entry), and is released over a different control? On
the LButtonDown message the csLButtonDown flag is set in the control's
ControlState, but how is this flag cleared later? It possibly will never
be cleared, when the BeginDrag method of a *different* control is invoked?
IMO the Delphi control model is flawed, when every control remembers the
mouse button states itself. IMO the position of a button-down and the
affected control should be stored in a unique place, e.g. in the TMouse
object. Then TMouse can handle all mouse moves and button events, and
will notify the controls only of definite events, like Clicks. Then also
the (immediate or delayed) begin of a dragging operation can be
determined and handled properly in the Mouse object. The same for a
mouse capture: it should be handled in one place (again in the Mouse
object), so that no control will ever have to handle captured events
itself, when instead the events have to be handled by the capturing
control, or by the DragManager.
Or did I miss something?
Of course it won't be a good idea to introduce such big changes into the
pending release, but IMO the following version should have a less
complicated, more stable, and less widgetset-dependent handling of mouse
events.
DoDi
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