What's the difference between Mouse Down? and regular Mouse Down events?

[cayenne]

Looking at event cases, I see one labled:

Mouse Down

And another as:

Mouse Down?

With the question mark at the end....what is the difference between the two? I don't see the difference described in the help menu...this is LV 2011 version.

Thank you,

cayenne

[AustinManinTown]

I am not sure how well the attached VI demonstrates what I am about to describe, but hopefully it helps.

The Event Structure can handle many different types of events from different sources. All these events can be put into 2 catagories, Notify Events and Filter Events. Notify Events are shown with a green arrow and no question mark after their name in the Edit Events dialog. Filter events have a red arrow and a question mark after their name. What is the difference?

When you configure the Event Structure to execute on a Notify Event the action associated with that event has been carried out. For example, the Value Change event is a Notify Event, so when you press the Stop button it changes from false to true on the front panel.

With a Filter Event an event is still generated, but it has not been acted upon. In the attached VI the other stop button generates a Mouse Down? event when pressed. Notice that the Boolean button does not change yet the event structure executes. Another Filter Event is Panel Close? This event executes when the user clicks on the front panel close button, in the top right corner. If we write a Boolean true into the Discard Event? input on the Event Filter Node (right hand side of the Event Structure) the event is 'thrown away'.

Hope the above helps. 

[AustinManinTown · Accepted solution]

Attached is another VI showing how a Filter Event is being used to change which mouse button appears to have been pressed. It is from the LV examples with some modifications made by me.