I have a simple form with three docked windows. The first is on the bottom, taking half the screen, then two equal size panels on the top. When I hide the left top panel, then the right top panel, then unhide them (in either order), the left top panel is only about 25 pixels wide (probably your default minsize), and the right panel takes up the rest of the top half of the screen. Shouldn't unhide restore the panel to it's original size? I don't want to set the minsize to half the screen because my users might want to make it smaller. I have tried responding to the resize event, but then the contents of the DockPanels get unsysnced with the DockPanel size, although they are set up to fill the DockPanels. I've tried setting PreferredDockSize in the form load, that does not seem to help.