Ah! I found the fix from an older forum post. I'll post it here just in case:
"VESTA remembers positions of dialog boxes and the Properties dialog box is probably shown outside of your display area. In that case the position should be automatically reset but that didn't work. Please try removing
VESTA.ini file in the same directory as VESTA.exe,
or if it does not exist,
%HOMEPATH%\AppData\Roaming\VESTA\"