A one-instance control checks to see whether the process started by the PUSH_ACTION is already running. If the process is not running, the PUSH_ACTION is run. If the process is already running, the window is moved to the top of the window stack in the current workspace.
Use these fields to define the control's behavior:
PUSH_RECALL: Set to True.
CLIENT_NAME: Specifies the name of the client to the control.
The value of CLIENT_NAME must match the first string (res_name) in the WM_CLASS property on the application's top-level window. For more information, see the xprop(1) man page.
PUSH_ACTION: Describes the action run when the user clicks the control.
For example, the following control runs one instance of an application whose action is named MyEditor.
CONTROL MyEditor { TYPE icon CONTAINER_NAME Top CONTAINER_TYPE BOX POSITION_HINTS 15 PUSH_RECALL True CLIENT_NAME BestEditor PUSH_ACTION StartMyEditor ICON MyEd }