Edit>Preferences>Window management and hit the Reset window position [...] button.
But the Tools option dialog docks like others. A common mistake is to drag it by its title bar instead of dragging the tab inside the window (like would would drag tabs between windows in Firefox and Chrome). Then you drop it in an existing dialog, if in the middle this adds it at the same position and creates a tab, near a border you get a blue highlight and the dialog is insert there, shifting/shrinking others.
But the Tools option dialog docks like others. A common mistake is to drag it by its title bar instead of dragging the tab inside the window (like would would drag tabs between windows in Firefox and Chrome). Then you drop it in an existing dialog, if in the middle this adds it at the same position and creates a tab, near a border you get a blue highlight and the dialog is insert there, shifting/shrinking others.