IME-unaware applications basically ignore all IME-specific Windows messages. Most applications that target single-byte languages are IME-unaware. When the user presses Enter or clicks a character to place it in a document, the IME, by default, posts either a WM_IME_CHAR message containing an entire DBCS character or a WM_IME_COMPOSITION message containing an entire DBCS string. If the application ignores either message, it falls through to the application's DefWindowProc, which in turn notifies the Input Method Manager that the message has been ignored. The IME then resends the character or string byte by byte via multiple WM_CHAR messages. Developers familiar with the Windows 3.x–based model will notice that the Windows 95 default behavior is more efficient, because Windows 3.x's default sends characters byte by byte rather than all at once.
Applications that are IME-unaware inherit the default user interface of the active IME through a predefined global class, appropriately called IME. This global class has the same characteristics as any other Windows-based common control. For each thread, Windows 95 automatically creates a window based on the IME global class; all IME-unaware windows of the thread share this default IME window. When IME-unaware applications pass IME-related messages to the DefWindowProc function, DefWindowProc sends them to the default IME window.