Closed Bug 576007 Opened 14 years ago Closed 8 years ago

Firefox crashes with Silverlight application as of 3.6.4


(Plugins Graveyard :: Silverlight (Microsoft), defect)

Windows XP
Not set


(Not tracked)



(Reporter: j_p_scott, Assigned: andy.rivas)



User-Agent:       Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; .NET CLR 2.0.50727; .NET CLR 3.0.04506.648; .NET CLR 3.5.21022; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729; .NET CLR 1.1.4322; .NET4.0C; .NET4.0E)
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv: Gecko/20100611 Firefox/3.6.4 (.NET CLR 3.5.30729)

I have quite a complex application (many UI elements etc. involved).  In FF 3.6.4 I am running into SL 4 stability issues when message boxes are shown to the user (System.Windows.MessageBox.Show()).

 In a test application this is not a problem (a plain silverlight page with standard MessageBox.Show()).

 But for some reason in my much more complicated application when a user clicks outside of the messagebox UI area the SL plugin freezes and then later crashes.  This was not an issue with previous versions of Firefox and only started happening when I upgraded to 3.6.4 with crash protection.

I tried disabling crash protection in FF 3.6.4 by setting about:config dom.ipc.plugins.timeoutSecs to -1 and that has improved the stability (by disabling crash protection).  With crash protection disabled, some message boxes respond immediately, some do not.  In one case I had to wait almost a minute before it responded to my OK click and closed it down.
 I can't at this time offer up the entire application for a repro and I'm working on a repro that eliminates some of the complexity to get down to a more minimal environment to repro the bug.

Has anyone encountered this besides myself?

Any ideas or anything to add?

Reproducible: Always

Steps to Reproduce:
Something to do with environment of complex application combined with SL MessageBoxes definitely causes the issue
Any messagebox that is up for more than the dom.ipc.plugins.timeoutSecs value will cause the hang detector to kill the silverlight process.

Sounds like bug 575226 comment 5 applies here.
OK, I might misunderstand this other bug.  I'm not sure it applies to my scenario.

I also have some direct steps to repro this error:

You need to enable windowless in the SL plug-in and then do some messageboxes in response to a button click.

See my solution for more info here:

Just click in the yellow square one or more times with FF 3.6.4 or higher and you will crash.

Now that we have an easy to repro scenario, hopefully we'll be able to get a great result out of this and get it fixed quickly.

Component: General → Silverlight (Microsoft)
Product: Firefox → Plugins
QA Contact: general → microsoft-silverlight
Version: unspecified → 4.x
Depends on: 540094
I don't see where it says a user can set the time out it -1 to disable ipc.  Can you show documentation somewhere that is support to work that way?  Because that doesn't look right.

If you want to disable IPC you do it this way:

dom.ipc.plugins.enabled = false
dom.ipc.plugins.[dllname here] = false

early crash times outs happen because the timeoutSecs is not high enough.
See bug 574905 - 3.6.6 up'd the timeout pref value from 10 to 45 seconds.
Hi everyone,

Maybe I have different results than anyone else, but timeout seems to have nothing to do with this for me at all.  It freezes immediately, doesn't matter what timeout I have set.

Hey James,

Microsoft does have a fix on our side that will be included in an upcoming release.  I cannot give you release dates but the update will be available this Summer.

Assignee: nobody → andy.rivas
Ever confirmed: true
This is WFM using Mozilla/5.0 (Windows NT 5.1; rv:6.0a1) Gecko/20110414 Firefox/6.0a1 ID:20110414030535 + Silverlight Version 5.0.60401.0.
Closing old bugs in the Plugins component. We aren't going to track issues in 3rd-party plugins in the Mozilla bug tracker. In addition, support for NPAPI plugins will be removed at the end of this year; for more details see the post at

If there is a serious bug in Firefox, it needs to be filed in the "Core" product, "Plug-Ins" component.
Closed: 8 years ago
Resolution: --- → INCOMPLETE
Product: Plugins → Plugins Graveyard
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