the pendingClick

[Richard Gaskin]

Controls that take different behaviors based on whether a single- or 
double-click has been received often limit the single-click behavior to 
selection, but reserve any action for the double-click.

For example, you may have an Inspector that updates when an object is 
single-clicked, but double-clicking the object may perform an action 
like opening a dialog.  Or in the Mac Finder, single-clicking an icon 
selects it, but double-clicking opens it.  Or a master-detail view in 
which single-clicking an item in a list updates the detail display, and 
double-clicking may trigger a default button in that layout.

Given the dexterity required to distinguish between single- and 
double-clicks, and that some OSes let you alternately use single-clicks 
for double-click actions which creates a very different set of user 
habits, it may be simpler for the user to put those two different 
actions in two different controls, or have some alternate means of 
distinguishing the action to be taken in response to an interaction.

Of course, in all fairness I have no idea about the UI in which this is 
proposed, so feel free to ignore what I've written.  But FWIW, offhand I 
can't think of a control I've encountered in any app in which both 
messages are used for actions, rather than the single-click being 
limited to selection and updating.

--
  Richard Gaskin
  Fourth World
  Rev training and consulting: http://www.fourthworld.com
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