Setting an existing project group as a default filter from the Groups dropdown
Select Projects > Project list.
Select one of these tabs:
Simple search.
Advanced search.
Action.
On the right-hand side, select the Filters dropdown.
In the Groups dropdown list:
Select the project group that you want to set as your default filter. To do so, hover over the relevant group.
Result: The group name is highlighted.
Select the white star icon
next to the project group that you want to set as your default filter. When you hover over the icon, the Set as default filter label is displayed.
Result:
The relevant group has been set as your personal default project filter. It is displayed at the top of the Groups dropdown and marked with the black star icon 
.
Note
You can only have one default project filter. So, if you have previously selected any other default filter, it will be replaced by your new selection.
Learn more about using, creating and deactivating default project filters.