I closed the "sidebar" windows (File, Resources, Structure, Attributes, Symbols) to gain more real estate in the main window. Now when I select them from the View menu, Dock Items, they are floating windows which I am unable to re-attach inside the main window.
You should put the cursor just under the top of the floating window (the cursor changes to a hand) and drag the window where you want it to be attached.
Same problem here. That's why I registered for this forum. At least I know I'm not the only one.
The outdated internal GDL code that handles the dock items has been removed from current CVS. Current CVS now compiles against your system installed libgdl. This should improve the way docks work.
One note, GDL is broken with Gtk 2.18 client-side windows. This still has not been fixed by the upstream GDL developers. You can work around the problem by starting screem with..
env GDK_NATIVE_WINDOWS=1 path/to/screem