[T-Mobile Samsung Galaxy S II SGH-T989] Splaktar:
This discussion started in this development thread: http://xdaforums.com/showthread.php?t=1623430

First off there are 2 different issues related to app hangs.

1) An issue with root apps hanging. This has been fixed with an updated superuser (@wraithdu v3.1) and Busybox (@wraithdu v1.19.4). This is not the issue being discussed in this thread.

2) An issue with non-root apps failing to launch. This includes random apps failing to launch from the app drawer and home screens (of various launchers, TW, Apex, GO, Nova). This includes the Phone app opening and displaying mostly a black screen. Existing apps that are open in the background still function and can be opened.

Issue #2 has been seen since Darkside released the first ICS ROMs. Specifically I have reproduced it in Evolution.3 Beta03, v1, v2, v4, v5.

Here are some of the relevant posts in chronological order:

Here is the first report that I found via search:

http://xdaforums.com/showthread.php?p=26006665&highlight=app+hang#post26006665

Another report with little info:

I posted here thinking that I might have fixed it (turned out I spoke too soon):

http://xdaforums.com/showthread.php?p=26170760&highlight=app+hang#post26170760

Another update from me:

And another:

A good post with some helpful information:

Reports from v4 start coming in:

The first suggestion that this is likely an app problem and that the ROM is fine:

A response to this being an app issue:

A claim that widgets that need root might be causing this. The only root needing widget that I use is Multi-mount lite and it has been enabled/installed during every app launch hang that I've seen.

Another report with very little information:

A response with a supposed quote that I don't see in the thread. I also late went on to test this and verify that this occurs even if you do not restore a single piece of data.

I finally start attacking the issue scientifically:

TDJ asks me to report back on my findings:

I start working on repeatable reproduction steps for the issue:

A theory about Busybox contributing to the issue emerges:

I look into it:

I report back on the status and respond to another theory that Superuser has something to do with the app launch hangs. I later reproduce the hangs on this same version that made it over 18 hours.

A good point is brought up about the lack of ALPHA kernel being in the OP subject line and that app launch hangs are not listed in the known issues section even after 10+ reports by users:

Reports start coming in about the issue happening in v5:

I report on my testing in v5 and post a set of fairly quickly reproducible steps:

I throw out the theory that this is an issue with the stock/ROM kernel:

I report back on my 100% clean v4 install and how it still hung. I talk about how the RAM is handled and that I don't ever seem to run out of RAM. The OS is freeing RAM from old apps and keeping my free RAM over 90 MBs all of the time. Also suggest that I will try to reproduce the issue on the stock rooted ROM.

A question about task killers and a claim that it might help manage the issue:

My response:

A confirmation that you can't open the Task Manager unless it is already running (and hasn't been freed) if you see app launch hangs:

OK, there might have been some posts missed that didn't include "app" or "hang" but that it all that I've gathered up for now.