Related Questions:
When editing a Booking name, the box keeps closing
When you try to overwrite text by selecting/highlighting the text using the cursor, the window closes off
Procedure:
When editing an item 'inline' by clicking on it, it automatically saves when you click away. This feature is called 'blur'. If you are editing text and you click/drag away from the inline edit (even a tiny bit), it exits/submits automatically.
Rather than click & dragging:
(which will often click 'out' of the text box)
Try double-clicking: