Handler.Box: destroy drag handler

[fredj]

Handler.Box creates a drag handler but forget to destroy it.

[fredj]

Handler.Box.destroy function

[bartvde]

Looks good fredj, please commit.

[fredj]

(In [10422]) Handler.Box.destroy: destroy the dragHandler. r=bartvde (closes #2697)

[bartvde]

I should have spotted that syntax error fredj :-) sorry about that. That's what I get for not running the code.

[fredj]

Replying to bartvde:

I should have spotted that syntax error fredj :-) sorry about that. That's what I get for not running the code.

Shame on me ...

[jcachat]

There is a problem with this patch. dragHandler is destroyed and nulled out before calling the base destroy method. If you step through OpenLayers.Handler.prototype.destroy it will eventually call back into Box.deactivate() if the handler was active at the time it was being destroyed. This causes a null exception in Box.deactivate() when it tries to call this.dragHandler.deactivate().

The solution I found was to change Box.destroy() to first call OpenLayers.Handler.prototype.destroy then take care of destroying the dragHandler.

[jcachat]

I should also mention that I may be experiencing this problem due to the way I am using the controls. I have a panel that contains a Navigation and ZoomBox control. If the ZoomBox control is activated and you use it to zoom to an area, then closing the browser triggers the null reference exception. I just noticed there is an example in the User Recipes section that is doing the same thing (http://openlayers.org/dev/examples/panel.html). If you modify that to use the trunk version of OpenLayers, it will demonstrate the problem.

[bartvde]

Changing milestone to 2.11 otherwise this ticket will not show up (Milestone 2.10 is in the past).

[fredj]

see #3003