Windows 7 window manager has recently started to behave strangely.
Firefox and Steam are running simultaneously. I am looking at the window of Firefox.
Now, I click on the Steam icon in the taskbar, the icon starts to blink in blue, and nothing has changed, I am still looking at the window of Firefox.
However, if I press alt-tab, I am able to bring the Steam window to the foreground.
The situation is then the same if I want to bring again the Firefox window to the forground.