What the title says basically. I'm able to switch between any of the preinstalled themes in alienbob's latest Plasma 5 build for -current fine, but as soon as I try too switch to one I downloaded my desktop just gets extremely sluggish and unusable while it's attempting to switch over to the plasma theme, which it doesn't seem to be switch over too successfully. I'm forced to be patient and wait for it to recognize my inputs so I can exit to console and delete the files the theme leaves behind in the .cache directory, and also deleting the theme file itself in it's .local subdirectory when I don't try changing back to a preinstalled theme before exiting Xorg.

I'm aware Plasma 5 isn't officially supported yet even in -current, but it's at least put out by one of the core developers so I figured it wouldn't hurt to ask on here about it.

This didn't happen before the kernel bump in -current also which I think is worth noting.

I can confirm this and/or you download a theme using system setting controls for doing so and it never shows up as a selection.
Also, Sweeper doesn't work. It just hangs and you have use the system monitor to terminate it.