How to add the tools window to a workspace?

Trying to make my own custom workspace, I had removed all the windows and wanted to put them back one by one to my liking.  Well, I FINALLY figured out how to add a "normal" window back onto the workspace, like the "libraries" window as shown in the picture where you can click and hold the tab where it says "libraries" and drag onto the workspace where you please.  However, this is apparently not the case with the tools bar that is sitting right next to it.. my brain is spinning and am confused as hell why this is so damn difficult and not easy to figure out.  So, I am seeing if anyone here knows how to solve this puzzle...