Move column opens menu on touch device

[AgDude]

On a touch device, holding on the column header opens the column menu, even when moving a column. My proposed solution is to make the "hold header to open menu" optional, and if you are using it with moveColumns you would turn that option off, so the user would need to touch the chevron button to open the menu.

[PaulL1]

I think we need to deal with each of the modes of operation and what we expect to happen in each situation.

So, for a mouse operation, we get:

• left click: sort
• left drag: move
• long click: open menu
• left click on chevron: open menu
• left drag on resize handle: resize

For touch devices, I think the intended behaviour is:

• tap on header: sort
• long click on header: open menu
• drag on header: move
• drag on resize handle: resize
• tap on chevron: open menu

So, same behaviour. For some reason I though the two were different but when I go through it they're not.

I think the problem is that the drag on header (aka move) also triggers long click. Perhaps it should not, so we're only getting one action - i.e. we need some way for the header to know we've triggered a move not a click. I think this area is perhaps the cause of #3333, so I think just disabling the long click isn't the right answer - we need to implement thresholds and clearly differentiate between a move and other actions.

[AgDude]

I think the difference is that dragging to move on a touch device there is an expectation of a delay where I hold in place util there is some indication I can drag. If we don't implement that, then people will be inadvertently moving columns when they are trying to scroll.

I opened #3767 for some broader discussion about events.