Ok, I understand these 2 events now.
But the first question stays unsolved.
I explain in details :
Suppose whe have a form with a cube, map, grid, dimtoolbar, rowtoolbar , coltoolbar connected alltogether is a sinle logic unit. The cube is already built and not all dimension are visible in the grid (so there is a button in the dimtoolbar).
Now suppose the user (1) clicks on a dimension-captioned button on DimToolBar and holding down the mouse button, (2) drags it(the button) over a RowToolBar and finally (3) releases the mouse button i.e. drops the button in the RowToolBar.
As a result to the three operations a new dimension is added to the rows.
The question is how , as a programmer, I can know what happened (from step (1) to (3)) i.e. what events occurred
and of course how can i cancel by code three steps if I need to do this restriction.
At moment (3) I wanna know which dimension is being dropped over RowToolBar. What is the way to satisfy my curiosity