I had some success with using SetWinPos to force a redraw of the background window. The following test script is functional if the keys arent pressed too rapidly.

<Hotkey Ctrl R> // PRESS CTRL R TO RENAME WARHAMMER WINDOWS
<RenameWin Warhammer War1>
<RenameWin Warhammer War2>


<Hotkey F1> //OPEN BACKPACK ON BOTH CLIENTS
<SendWinx War1>
<Key B>
<TargetWin War2>
<SetActiveWin>
<wait 30>
<SendWinx War2>
<Key B>
<TargetWin War2>
<SetWinPos 1000 0>
<wait 30>
<TargetWin War1>
<SetActiveWin>




<Hotkey F2> //OPEN HELP WINDOW ON BOTH CLIENTS
<SendWinx War1>
<Key H>

<TargetWin War2>
<SetActiveWin>
<wait 30>
<SendWinx War2>
<Key H>
<TargetWin War2>
<SetWinPos 1000 0>
<wait 30>
<TargetWin War1>
<SetActiveWin>