Descriptive Problem Summary:
This issue is present as of the 507.1284 build. There is no problem when playing via the Dream Seeker.

Screen objects don't disappear when removed from client.screen in the webclient. It seems like the screen needs to be "updated" again in some way for the change to take effect. For example, after you remove an object from client.screen the objects will only disappear once you add a new object, or if the player moves.

It looks like part of this issue may have been addressed before, but I'm still seeing the problem: http://www.byond.com/forum/?post=1818775


Numbered Steps to Reproduce Problem:
My old hud demo is a good way to demonstrate what's happening.

1) Load the demo into the webclient and click the "OPEN Menu" button.
2) Try moving around a bit, and the menu stays on the screen (as intended).
3) Click the "SHUT Menu" button. This should close the menu, but nothing happens.
4) Move again and the menu will now disappear.

Link to demo: http://files.byondhome.com/SilkGames/bugs/ silk_huds_silver_v1.zip