@oransen
It is a basically a toggle for this button (for styles)

When the project file is set to read/write the save button is enable and thus allows you to save your styles back to the global styles or the styles that are in XML form in your designated design data folder. Have this enable allows any user having this option to do this.. In my opinion its a bad thing because at some point it will lead to a styles conflict.
Update: @Lewis.Young This statement ":When the style library is set to read-only you can only use the styles and not edit them" is not really 100% true..
There's local and global styles. Local styles can be modified even when the the styles library option in the project file is set to read-only. If its read-only the user is not permitted the save option and thus they are unable to save back to the global styles.
Mark Lancaster
& Autodesk Services MarketPlace Provider
Autodesk Inventor Certified Professional & not an Autodesk Employee
Likes is much appreciated if the information I have shared is helpful to you and/or others
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