_root.onLoad function is not called

[ydalton]

Describe the bug

The contents of the _root.onLoad function in a SWF is not run.

Expected behavior

_root.onLoad should be called.

Content Location

I ran into this while making a small game, but I have made a SWF demo of the bug.

Stage code:

_root.onLoad = function()
{
	mainText.text = "_root.onLoad was called";
};

Expected result (Flash Player):

Actual result (Ruffle):

SWF file: onload.zip

Affected platform

Desktop app

Operating system

Gentoo Linux

Browser

No response

Additional information

No response

[Lord-McSweeney]

See #1820 and #11772