Draw marker during drag and rectangle during zoom

Hello!
I am new to Qwt and I have a persistent problem which I cannot solve, so I decided to ask for help.

I plot a histogram and set markers in form of vertical lines on it. These markers divide my original histogram into many small colored histograms. I derive from QwtPlotPicker and override widgetMouse..Event() functions in order to catch mouse events and place markers on mouse click. Now, if I want to move an existing marker, I use the same MyPlotPicker instance as before. I store the start and end position of the mouse drag and move the marker into the new position. But I cannot persuade MyPlotPicker to draw a temporary marker during dragging. I tried drawing a marker on-the-fly in void MyPlotPicker::widgetMouseMoveEvent( QMouseEvent * event), but it did not work out.

I also use MyPlotPicker for zooming. If a drag is performed during right-button mouse click pressed, I interpret it as zooming into the selected area. Here, again: I do not know how to draw a rectangular selection in the area where I want to zoom into. I have tried reloading drawRubberBand, but the function seems to never be called. Any idea as to what am I doing wrong?

I use the Qwt 6.0.0 RC5 under Windows with Qt 4.6.1.

Thank you in advance!

I have added the itemeditor example to SVN trunk. It demonstrates how to use the new QwtPlotOverlay class for building some sort of graphical editors.

Maybe it helps,
Uwe

Thank you very much! Your example has helped me implement my own marker dragger.