I add a DockPanel with:
m_panel_1 = dockPanelManager()->addDockPanel(tr("Panel 1"), QSize(300,200),LeftDockPanelArea);
If i move the panel with the mouse to make the panel floating it behaves different to version 2.0.1.
With 2.0.1 the floating panel has the size of sizeHint. This is good. With 2.3.0 the floating panel has the same size as the docked panel. In this case, sizeHint is senseless.
I have checked this demo Docking_SimplePanel.
If I switch m_panel_1 to floating over the menu entry Panels->Panel 1->Float the floating panel has the same size as the docked panel in both versions.
In any case, switching a docked panel to a floating panel sizeHint should be used or size of the panel before it was docked