QWidget::SetCursor does not change cursor immediately on Windows

We are using QT 4.7.0 libraries for a desktop application. One of our requirements is to momentarily set different cursor shapes for different widget while the application is processing a particular piece of code. Hence, we use QWidget::setCursor() to set the cursors on the widgets. Though the code works fine as expected when run on Linux platform, the behaviors is broken on Windows platform. We observe that on Windows platform the visuals for the cursors shapes don't get updated immediately; and the cursor is updated only after a while. During that period it shows a single cursor shape for all the widgets irrespective of different cursors set for different widgets.

This problem would happen as following:-

1 Set of panel (widget) are up
2 In for loop set all widgets cursor to different value
3 Perform lengthy task
4 Restore normal cursor for different-2 value

Here even after performing step#2, I do not see its effect for some time while step#3 is being performed. I expect that cursor is set correctly immediately after completing step#2.

I have developed a sample program to demonstrate this behavior. Please check the source code attached. Please follow the instructions in the README.