Last, and certainly not the least, of the buttons types is Split. This is available at the group and cluster buttons.
Here we have a group level button that spans the entire height of the group, with the mouse tracking over the click area.

And now tracking over the drop down area.

When you click the drop down area it shows the associated context menu strip.

The same button in the medium size also honors the split type.


The cluster level button can be configured to be split. Here you have the click portion pressed down.

Finally we have the drop down area of the cluster button pressed.

It seems to have taken forever but we now have the full spectrum of button functionality in place. You can have a push, check , drop down or split type. All the types of button are available as large, medium or small sizes and can also be placed into clusters. Phew.
Now onto the actual auto sizing of the groups to handle the ribbon being resized to different widths. I want to make this process as seamless as possible so that the developer doesn’t have to start specifying complex priorites and other values. It should just work in a reasonable way straight out of the box.