Illustrator collapses swatch panel?

Hi guys,

I have an issue with Illustrator CS6, running on 10.6.8...

I'll have an object selected, and I'll be using my Swatches panel to edit the colour of the object's fill, let's say. Then I will want to edit the colour of the stroke – as soon as I hit the stroke square in my toolbox, the Swatches panel disappears and the Color panel jumps out instead. I have to close the Color panel, and then reopen the Swatches every single time.

Workspace: "Essentials"

I don't have the Auto Collapse Iconic Panels on...

Thanks!