If KC_CHAR is the mnemonic for a button that already has the focus, a BM_CLICK is sent to that button and rc is set to TRUE. If the button does not have the focus, it receives the focus and rc is set to TRUE.

If usvk contains the value VK_TAB, the focus is set to the next tab item in the dialog. rc is set to TRUE.

If usvk contains the value VK_BACKTAB, the focus is set to the previous tab item in the dialog. rc is set to TRUE.

If usvk contains the value VK_LEFT or VK_UP, the focus is set to the previous item in the group. rc is set to TRUE.

If usvk contains the value VK_RIGHT or VK_BOTTOM, the focus is set to the next item in the group. rc is set to TRUE.

If usvk contains the value VK_ENTER or VK_NEWLINE, and a push button has the focus, a BM_CLICK is sent to the button and rc is set to TRUE. If another control in the dialog has the focus the dialog is searched for a push button with style BS_DEFAULT. If a push button of this style is found, a BM_CLICK is sent to that button and rc is set to TRUE.

If usvk contains the value VK_ESC, WM_COMMAND is posted, with ussource is set to CMDSRC_PUSHBUTTON and uscmd is set to DID_CANCEL. rc is set to TRUE.

In other instances, if an owner exists the message is sent to the owner, otherwise rc is set to FALSE.