Keychain won't let copy passwords after 10.11.1 update

After the 10.11.1 update, I can not get access to some of encrypted data stored in my keychains with Keychain Access.app. Most notably, I can not see or copy passwords stored.

Normally, to do so, you'd have to:

1. unlock a keychain with keychain password;
2. unlock an item itself with keychain password.

During 2nd step, when password is typed in, you can select 2 options: "Allow" and "Always allow". The difference is that if you click "Always allow", you won't have to perform 2nd step for this item again.

Here's some things I was able to detect:

• if I had clicked "Always allow" on an item before OS X update, I can access it fully;
• if I haven't clicked "Always allow", I can not copy password from right click menu, nor see it when ticking "Show Password" checkbox on Info Screen.
• if I add new item, I can not copy password from right click menu, but can still see it on Info Screen.

I get what seems to be mostly full keychain data using following command (though, I am not sure everything's there):

security dump-keychain -d elmigranto.keychain

UPD: After more detective work, I found following message appearing in Console.app when I click anything in password dialog:

26.10.15 10:19:52,345 SecurityAgent[770]: Ignoring user action since the dialog has received events from an untrusted source

UPD2: Pretty sure this is caused by HT205375, which among other changes lists the following:

SecurityAgent

Available for: OS X El Capitan 10.11

Impact: A malicious application can programmatically control keychain access prompts

Description: A method existed for applications to create synthetic clicks on keychain prompts. This was addressed by disabling synthetic clicks for keychain access windows.

CVE-ID

CVE-2015-5943

Third-party utilities such as Alfred, TextExpander, or MagicPrefs might appear to take "control" of the window as far as the OS is concerned. You can find the culprit by disabling them all, and turning them on one by one until you find one (or more) which affects Keychain in that manner.

You can add the offending program to the list of approved apps ( System Preferences -> Security & Privacy -> Accessibility ) and this issue will go away. (hat tip to @elmigranto for this addenda)

I had this problem trying to edit the keychain while screen sharing. Even when I had direct access to the server, if the other computer was still screen sharing, it would fail in this way. After stopping the screen sharing and making the changes directly on the server, it worked.