Both companies were hoping that at some point users would migrate to OS/2. In 1990, version 3.0 of Windows was beginning to sell in volume, and Microsoft began to lose interest in OS/2 especially since, even earlier, market interest in OS/2 was always much smaller than in Windows. The companies parted ways, and IBM took over all of subsequent development. Microsoft took OS/2 3.0, which it renamed Windows NT; as such, it inherited certain characteristics of Presentation Manager. IBM continued to develop Presentation Manager. In subsequent versions of OS/2, it was used as a base for the object-oriented interface Workplace Shell. In latest versions, IBM has commissioned SciTech Software with writing the graphics drivers for the majority of the cards that don't support OS/2 officially. There is a significant integration of the GUI layer with the rest of the system, but it is still possible to run certain parts of OS/2 from a text-console or X window, and it is possible to boot OS/2 into a command-line environment without Presentation Manager (e.g. using TSHELL ). PM follows the Common User Access interface conventions. It also supports mouse chording for copying and pasting text. An important problem was that of the single input queue: a non-responsive application could block the processing of user-interface messages, thus freezing the graphical interface. This problem has been solved in Windows NT, where such an application would just become a dead rectangle on the screen; in later versions it became possible to move or hide it. In OS/2 it was solved in a FixPack, using a timer to determine when an application was not responding to events.