# Click the '''OK''' button of the dialog to accept the changes and close it.
Once you create a new block node has been created on the navigation tree, it becomes the "Active" groupof the project workspace, which is always displayed in bold letters. Then you can always changes start drawing new objects under that node. Any block group can be made active by right clicking on its name in the navigation tree and selecting the '''Activate''' item of the contextual menu. Â You can always change the properties of a block group later by accessing its property dialog from the contextual menu. You can also delete a block group with its objects at any time.
=== Buildings & Obstructing Blocks ===