You can select one or more boards in the Hostview main window. You can also select one domain in the main window. You must select a set of boards prior to performing certain operations, such as creating a domain.
To select a single board, click on it with the left mouse button. The selected board is indicated by a black outline, and all other boards are deselected.
To select additional boards, click on them with the middle mouse button. You can also deselect a currently selected board by clicking on it with the middle mouse button. (The middle mouse button toggles the selection status of the board without affecting the selection status of any other board.)
To select a domain, click on a board within that domain with the left mouse button. Note that you can select boards from different domains (using the middle mouse button), but the selected domain will correspond to the board that you selected with the left mouse button.