The timeline view is an incredible helpful one and when looking for free spaces in the timeline it would be great if you could just start the creation of a new reservation directly from there.

Here is my suggestion: Right click on a free space in the timeline to start a daterange selection. With pending daterange selection right click to cancel the daterange selection left to complete. If with a active daterange selection you click anywhere invalid the selection is cancelled to.

When a daterange is completed you jumo into the create reservation view and skip step 1 (daterange is applied) directly into step 2 where the choosen space is selected in the dropdown.

An alternative handling for creating a daterange selection in the timeline would be to right click and hold. This alternative could be used in addition to the handling above.

When already adding behaviour to the timeline it would bee useful to allow rightclick on reservations to directly jump into reservation edit instead of preview.