I would highlight the "Every tick" line within the block, and delete it. Then just highlight the main block which will now only have the "Every 0.3 seconds" condition, and press "S" on the keyboard. This will add a new Sub-Event. Then set up the "Every tick" as the sub-condition. If that is your intention.
Then just drag any events that belong under "Every tick" sub-condition down to the block to the right of it.
Dragging and dropping Events/Actions should change the highlight line of where it will go, depending on the position it is dragged to. In this case, it's probably easier to just delete the line, create the sub-condition, and drag the events in. If you are having a tricky time getting it to drag to the correct position...