1.Can be edit the ui extension file outside the qt designer....in any editor??If yes then what step will take.

2.ClassA
{
.....
.....
};
Class B : Q_Object
{
...........
..........
};
Can be do the singnal and slot mechanism between these classes if yes then how.

3.Can we use both horizental and vertical layout in the same dialog.Can be use the horizental layout twice in a dialog.If yes then what error will occcur.