Page selection bad UI design

Create a sitemap item in the URL designer.
Scroll through the available page designs using the arrow buttons until you find one to your liking (but don't click on anything).
Click save.
Select another sitemap item.
Select the first sitemap item again.
The selected page design has not been saved.

This is because after clicking the arrow buttons, the user has to click one more time on the thumbnail to actually select the page design. The background will become grey to indicate it has been selected.

None of the people I have seen using the HST editor (including myself) did this right the first time, and each one got frustrated because apparently the page selection did not get saved.