Not currently. Like recent versions of Office, UR implements MSDI (multi SDI) as opposed to MDI. Enabling 'Tools | Options | General | Minimize to system tray' and minimizing unused dbs may make things more useable. Also see
http://www.kinook.com/Forum/showthre...?threadid=1775
One advantage of the separate top-level windows is that if a long-running operation (for instance, importing) is happening in one database, you can still switch to and do stuff in another database (although you must switch via the task bar or Alt+Tab rather than the document toolbar in this situation).
Some Alt+Tab extenders/replacements that can also be helpful:
Exposer
http://www.onlinetoolsteam.com/WindowsExposer/
SmartTab
http://www.smarttab.org/
TaskSwitchXP
http://taskswitchxp.sourceforge.net/
TopDesk
http://www.otakusoftware.com/
WinGlance
http://www.usablelabs.com/productWinGlance.html
WinPLOSION
http://www.winplosion.com/
XSwitch
http://www.edgebeyond.com/products/xswitch/