Hello everybody, This will take a little while to describe the problem I'm facing, and I will appreciate your patience. I'm creating a pretty large SDI MFC application, with a lot of options and controls. Most of the application screens are list based. If that matters, imagine MS Word 2007 with editable list instead editable document. Some of the controls activate a pretty lengthy operations that do work on the list, and update its entries. These operations use worker threads to do their work. Now, the problem. I want to update the list on the go while disabling all the controls, except one - the "cancel" button. A simple EnableWindow(FALSE) wouldn't work, as the application is Ribbon based. I.e. to make the buttons look disabled I must handle ON_UPDATE_COMMAND_UI. Simple message pump wouldn't work as well, because of MFC message routing. Can anybody suggest a proper approach for such an application? That is both relative simple and general (I have many different operations that activate worker threads).