Altering transparency of Firestorm windows?

[Resi Pfeffer]

Hi,

i wonder, if there is a possibility to change the opacity/transparency of the windows in the firestorm viewer?  Like the inventory, chat, map and so on...
Even though, SL runs on Full HD, text size is set to "small" and windows are resized to be as small as possible, i still feel like, my view gets quite limited when chat and inventory is opened, for example.

Would like to change it to be more transparent in general, no matter if the focus is set to that window or not.
Any ideas? Searched already the whole settings menu and all the tabs...

Edited October 23, 2018 by Resi Pfeffer
typo

[KT Kingsley]

There's Floating Window Opacity/Active in Preferences/Colors/Miscellaneous.