What problem does this address?

Currently, you can't set the height of a spacer block if that block is a direct descendant of a Row block. Instead, you get the width controls that all blocks get when they are direct descendants of a Row block.

However, you might still want to adjust the height of a spacer block when it's inside of a row. On a site I'm working on right now, I have the spacer inside of a row that's set to "Allow to wrap multiple lines", and I want to use the spacer to add extra height to the bottom of the row on mobile, when the blocks inside the row are stacked.

(In this situation, the block description in the top right – "Add white space between blocks and customize its height." – isn't correct.)

Since the height setting is not available, my workaround is to wrap the spacer inside of a group so I can set the width on the group and the height on the spacer, but it's not a great solution.

What is your proposed solution?

When a spacer block is the direct descendant of a Row block, allow the user to set both the width and the height of the spacer.