Handling a common event like a double click is not so simple as we may assume when it comes to Flex programming.
In fact there are several critical aspects related to this event, first of all we have to set the attribute doubleClickEnabled to true in order to make our components double clickable, and this sounds pretty silly to me. Why should I enable an object to receive an event which is so common and “natural”? This is incoherent from a software design perspective end totally unexpected by the user. Anyway this is not a real problem, because once we know about it we have just to use a setter, but double click is somehow buggy in the framework and its broadcasting can be blocked mysteriously when using certain components. I faced this issue by trying to handle a double click on a DataGrid which makes use of custom item renderers and I tested that by double clicking on the “special cells” (those rendered by my own renderers) the MouseEvent.DOUBLE_CLICK is not dispatched/cacthed. To solve the problem I had to draw an invisible rectangle using the underlying Actionscript graphics API! This is my workaround:
this.graphics.drawRect(0, 0, this.parent.width, this.parent.height);
Finally, it seems that double click is completely ignored by Firefox 3.6 on Mac OS X, but fortunately this seems to been fixed in the last release (3.6.3)