resize/move selectors visible even when widget is hidden

Steps to reproduce:
1) create a new MultiPageWidget from the 'custom widgets' section of the wizard
2) add a second page to the MultiPageWidget
3) go back to first page
4) place a qpushbutton on the first page
5) switch to the second page
-> the qpushbutton is hidden (as it should be) but its resize/move selector is still visible