456650 - Fail to unload plugins when switching away from a complex page

Status: RESOLVED INCOMPLETE

(Core Graveyard :: Plug-ins, defect)

Description

[Kaz F]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.0.1) Gecko/2008070208 Firefox/3.0.1 (.NET CLR 3.5.30729)
Build Identifier: Mozilla/5.0 (Macintosh; U; Intel Max OS X 10.4; en-US; rv:1.9.0.1) Gecko/2008070206 Firefox/3.0.1

Firefox fails to unload plugins when switching away from a complex page.

If CanSavePresentation() returns false for a page, then plugins embedded on that page will not get the required Destroy()/Shutdown() calls. When CanSavePresentation() returns true, the plugins does get the calls.

This may have to do with StopPluginInstance() being invoked in PresShell's Freeze() function rather than PresShell's Destroy() function. The problem doesn't seem to be happening on Windows XP.

Reproducible: Always

Steps to Reproduce:
All steps provided in the Details section. There are no fine grained steps to follow. Use any plugin that embeds into the page and provides some visuals.
Actual Results:  
The visuals from the plugin remain overlayed ontop of the new contents in FireFox. The plugin is unresponsive (it looks as if it stops getting HandleEvent calls).

Expected Results:  
Unloading the plugin by calling Destroy()/Shutdown().

On a side note:

You can force plugins that haven't gotten Destroy()/Shutdown() to get Destroy()/Shutdown() by opening up a new tab, then going to File->Close Window. Once the dialog box opens up asking you if you'd like to save the tabs, the plugin gets the Destroy()/Shutdown() calls.

Comment 1

[Benjamin Smedberg]

Resolving old bugs which are likely not relevant any more, since NPAPI plugins are deprecated.