There is a strange behaviour in DateTimeCellModel.
Example attached.
Step 0: Run attached solution
Step 1: Single click on one of grid cells
Step 2: Now click on the textbox in right upper corner
Step 3: Click on "dropdown" button (with small triangle) in previously clicked cell
Calendar appears in right bottom corner of the screen. How can I fix this problem?
DateTimePickerCellBug.zip