Inconsistency
An example of a program that violates the expectation that pressing Alt+Tab ↹ one time will switch to the previous application is Adobe Reader 7.0.x. Like newer versions of Microsoft Word it attempts to give a separate icon in the Alt+Tab ↹ task menu to each MDI document. However, unlike Word, it brings two items to the front of the list whenever a document is selected using Alt+Tab ↹: first an icon representing the main Reader window and then an icon for the individual document. While in Adobe Reader, pressing Alt+Tab ↹ one time selects the second item in the list, which is the icon for the PDF document. Adobe Reader remains the current task when Alt+Tab ↹ is released. Thus it is demonstrated that the correct operation of Alt+Tab ↹, like some other aspects of the Windows environment such as the Clipboard chain, depends on individual applications being written correctly.
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