Is there a way to change the font in the single record view window?
No, there is not a way to change the font in the single record view window.
If you would like to vote on this to be an enhancement in a future version of Toad for Oracle, click here and vote for it.
If you require to view multi-byte characters such as Japanese or Chinese in the single record viewer, then it will be necessary to install
Windows
'Supplemental Language Support'
Start | Control Panel | Regional and Language options | Languages