The behaviour is following:
- when the refresh button is pressed
1. it calls the refresh function of QMyFigContainer
2. QMyFigContainer first switch data from 1 to 2
3. then destroy the former figure
4. Recreate a figure with the new data
5. attribute the figure to the canvas
5. Resize the canvas and QMyFigContainer
6. Then resize the QMyDesignWidget
7. Then resize the QMyDesignGui
8. Then call the paintEvent from QMyDesignWidget that draws the Canvas of QMyFigContainer.

A bit complex I know...

Maybe a better way