This morning, On my Macbook Pro, I was able to use the option-tab shortcut to cycle through windows within an application. This afternoon, when I do the same keystroke, I just get a tab character. Or I cycle through the links on a website. The option key is working, as I can use other keyboard shortcuts. I even plugged in an external keyboard and it is responding to the option key. But the shortcut option-tab appears to no longer be working. I have the fear that I accidentally pressed some weird key combination without realizing it that remaps the key for accessibility purposes. I've looked around the system preferences and I can't see anything that would reassign the combo. Does anyone have an idea of what happened?