Have you ever started entering a value into the Properties panel and then accidentally bumped the cursor off from the Properties? After doing so it automatically applies the incomplete property value. It can be frustrating at times.
This can be avoided by a manual entry into the Revit.ini file which will disable this functionality.
- Open the Revit.ini file found in the folder C:\Users\AppData\Roaming\AutodeskRevit
- Under the section called [UserInterface] type DisableMppAutoApply=1.
- Restart Revit.
Now the property value won’t be applied in the Properties until you either press the Apply button, or click back into the model space.