#1673 Panel edit doesn't follows main panel on right screen when there are severals

[Trebly]

When the users uses several displays the localization of the edit panel (may be others panels) do not take care of the fact that the main panel can have been moved from a screen to another.

Consequence : When the user opens a task to edit, the edit panel can appear far from the main panel on another screen at the old place of the main panel.