It is possible to re-signal a Trigger as a shortcut of dragging in additional Trigger instances for signalling.
Display the Simulation Events window, then right-click on a Trigger within that window and select the 'Re-Signal Selected' option.
Simulate > Dynamic Simulation > Triggers > right-click on existing trigger > Re-Signal Selected
The Simulation Events window contains a list of Triggers that have already fired. By right-clicking on a Trigger that you want to signal again, you can use the context menu to cause the re-signal to happen.
This image demonstrates resignalling in action. When a signal is re-signalled, a new copy is made and placed at the end of the signalled triggers list, where it is automatically fired again.