Web parts contain certain common properties that define system settings and general web part behaviour. This includes the properties from the following categories:
•Visibility / Usability
•Web part container
When a new web part is created, these properties are loaded from XML files, which can be found in your website installation directory under the ~/App_Data/CMSModules/PortalEngine/Properties folder. Each category of properties has its own xml file under the _Groups sub-folder. These categories are then defined for specific types of web parts through the files under the WebPart folder (and its sub-folders).
This tab allows you to specify the default values of these properties for the currently selected web part. This can be done by clearing the Inherited checkbox and entering the new value into the appropriate field. Setting these values only affects the default property values of newly created web parts, it won't change the properties of existing web parts on the pages of your website.
If you wish to modify more than the default value of one of these properties, such as its behavior and attributes (e.g. for it not to be displayed in the web part configuration dialog), you can do so by adding and configuring it on the Properties tab. Please be aware that doing this will prevent the given property from being displayed on the System properties tab.
More resources can be found at: