When creating an event and then clicking on close without having clicked on safe it closes the window and nothing is saved. To avoid this (and as it is redundent anyway) this should be removed.
Steps to reproduce:
1. Create an event.
2. Click the "x" on the upper right corner.
Actual result: Event is discarded
Expected result: As the x does the same as the Cancel button on the bottom (which is always visible) I think we do not actually need the x.