introduce this new signal: make sure the size of the dialogmake sure after a showevent the size is final and the
dialog can be safely repositioned.
get rid of show and hide of mainItem (as opposed to its window)
since it had repercussions on the size calculation, giving it
a stuttering appearance when windows appeared.
is final, sinced withif we want to position the main item and the optional layoutwindow when we are sure the size is final
afterand the abouttoshow signal and right before actually showingwindow is not shown yet (but about to) we can
it: clients with custom positioning can safely position the dialogdo it in the signal handler of visibleChanged (when visible is true)
in its signal handler as they know it won't resize when shown.we are assured we are right before the expose event
this makes synctomaintem and updatelayoutparameters working even if
the dialog is not visible as we need to resize beforehand
first user of this will be the notifications applet