Tn5250: can't move window

Official 41414.
tn5250 is a telnet 5250 terminal emulator, you can test it (just to see this bug) by typing an IP with a telnet daemon enabled. Once connected it'll show the main screen which can't be moved in ros, neither clicking on the title and dragging the window, nor right clicking on the title and clicking on move and moving it with the cursor, the window is fixed in its position. Same thing works in xp.