When the last window to remain open isn't a browser window (but the download manager for example), you cannot open a new window by clicking the (pinned) firefox icon on the taskbar. It will minimize/show the last non-browser window. I find this very counter intuitive. Steps to reproduce: - Open Firefox by clicking on the firefox icon on the task bar - Open Download manage - Close browser window - Click on the firefox icon on the task bar Expected behavior - show a icon tile to open a new window (containing firefox icon) - show the window tile for the download manager (containing scaled down window of download manager) Current behavior - minimizes the download manager I've attached how Live Messenger solves this issue. Workaround 1) Close the download manager and click the firefox icon on the taskbar again 2) Or, right-click the taskbar icon and select "Mozilla Firefox".

This isn't very discoverable, but you can always shift-click or middle-click.