Hi,

I don't know if it's a bug, so I'm just asking here... Look at my htop output:
http://i.imgur.com/hf7D1Fp.png

plasmashell is taking up 9.8 gb of virtual memory? Is that normal behaviour?

Virtual memory is the required address space, it eg. raises drastically when mmpping a huge file to read sections from it.
I assume it rose for you because you tried some themes or similar.

In general, the value is unspecific and not a problem unless you run out of address space (32TB on a 64 bit system
It has *no* relation to the memory actually being used by the process.