Make Multiple Taskbar Buttons Automatically Switch to the Last Active Window contains the registry files that allow you to open the last active Window with a single-click when a program has multiple windows open. Video tutorial available.
As you already know, all apps with multiple Windows open are found in a single button on the Taskbar. You can line your mouse over, then click on the window you want to open, or press CTRL and click and scroll through the Windows. With a simple registry change, we can make it, so you only need to click to open the last active window simply by clicking the Taskbar icon.
In our screenshots below, you can see a before and after as much as possible.