Annoyed with the time picker pop-up bugging out and staying on-top even after it have lost its focus? Knack support have reported to me that they are working on a permanent fix, but in the meanwhile you can disable it with a line of CSS code.
See the bug here:
https://uploads.intercomcdn.com/i/o/2067295/922f4adeee47813acc2d1fd8/click%2520timepicker.mp4
Just add the following to your CSS code:
ul.ui-timepicker-list {display:none !important;}