OFFBEAT Big Blue escalated the OS/2 keyboard squabble through seven layers of management. Redmond's answer? Nope Long before Copilot or even the Windows key, Microsoft and IBM were squabbling over Tab - a tale that says more about Big Blue's bureaucracy than hopping between fields. Veteran Microsoft engineer Raymond Chen  shared another war story  this week, from the time IBM and Microsoft were at loggerheads over the Tab key during the OS/2 collaboration.  This wasn't the tabs-vs-spaces debate that has long rumbled through the IT world (another Microsoft veteran, Larry Osterman,  came down firmly on the side of tabs  when storage was tight, then switched spaces when it wasn't). This was simpler: which key should move you between fields in a dialog box. Microsoft's preference was the Tab key. IBM strongly opposed the decision.…