The Parser branch under Configuration - IDE - IntelliTips has the following options:
Auto re-parse documents when saved
When this option is selected UEStudio will automatically re-parse the saved document for items to be provided in the IntelliTip list.
Parse extensionless files as
Users may specify a file extension to be used by default for parsing for files that are saved without an extension.
Do not use cache for symbols
This option will force UEStudio not to use the cache for symbols in the active project. By default this option is not selected. Check this only if you have very low disk space.
The cache is in the %APPDATA% directory. If the cache is not used then the parser has to re-parse everything every time rather than working based on dependency checks (when files are updated or changed). Therefore the use of the cache is recommended for performance reasons.
Clear Cache
This button may be used to force UEStudio to clear the cache.