Regarding the spell-checking dictionaries, have you installed them via Tools->Spell-checking dictionaries in Xbench?
If you downloaded the dictionaries from some other source (for example Xbench 2.9 dictionaries from our blog), they may not show up. Using Tools->Spell-checking dictionaries, ensures that the right 32-bit or 64-bit dictionaries are installed.
Regarding the Xbench plugin for Studio, please ensure that you are using the latest installer from our Download page.
You should not need to restart your computer after installing the plugin, but Studio needs to be restarted. If after ensuring that you use the latest installer from our website does not help, please contact us via our support page and we'll try set up a Teamviewer call to try to troubleshoot it.