I prefer to have the Building Blocks panel on the left and Blueprint panel on the bottom of my client.

I can drag the Blueprint panel wherever I want.

In puzzle 1561, when I grab the Building Blocks panel by the top of the panel and drag it to the left, it disappears
if I drag it across the Rank/Score box at the top
and cannot be reopened by clicking the "Building Blocks" button in the Blueprint panel.

(It does not disappear if I carefully duck it under the Rank/Score box.)

Once it disappears, the only way I can see the Building Blocks panel again is to close the client and open a new one.

I'm using main, Build ID 20180725-d14dae34c3-win_x86