Hotkey <kbd>O</kbd> problem?

Describe the problem you’re having:

Error appears on popup window within TTRSS when trying to open article using the hotkey O.

New window opens with url for about:blank

If possible include steps to reproduce the problem:

Three-pane window, vertical. Select article in middle pane, press O.

tt-rss version (including git commit id):
Platform (i.e. Linux distro, PHP, PostgreSQL, etc) versions:

tt-rss version (including git commit id):

# git rev-parse --verify HEAD
4ea407f613b40a0117ff74fba755464e7239f508

Platform (i.e. Linux distro, PHP, PostgreSQL, etc) versions:

# cat /etc/issue
Ubuntu 18.04.4 LTS \n \l
# uname -a
Linux li1004-82 5.3.0-53-generic #47~18.04.1-Ubuntu SMP Thu May 7 13:10:50 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

# php --version
PHP 7.2.24-0ubuntu0.18.04.6 (cli) (built: May 26 2020 13:09:11) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.2.0, Copyright (c) 1998-2018 Zend Technologies
    with Zend OPcache v7.2.24-0ubuntu0.18.04.6, Copyright (c) 1999-2018, by Zend Technologies

# mysql --version
mysql  Ver 14.14 Distrib 5.7.30, for Linux (x86_64) using  EditLine wrapper

# psql --version
psql (PostgreSQL) 10.12 (Ubuntu 10.12-0ubuntu0.18.04.1)

# grep DB_TYPE config.php
        define('DB_TYPE', 'mysql');

Please provide any additional information below:

Stack trace as appears in popup window, anonymised Unhandled exception

NS_ERROR_MALFORMED_URI:
Stack trace:

i/<@https://myhost.example.com/reader/:1:1097
postOpenWindow@https://myhost.example.com/reader/js/App.js?1601636202:174:9
openInNewWindow@https://myhost.example.com/reader/js/Article.js?1601636202:135:7
initHotkeyActions/this.hotkey_actions.open_in_new_window@https://myhost.example.com/reader/js/App.js?1601636202:953:24
hotkeyHandler@https://myhost.example.com/reader/js/App.js?1601636202:824:24
initSecondStage/document.onkeypress@https://myhost.example.com/reader/js/App.js?1601636202:682:54
Console log
keyeventToAction o => open_in_new_window App.js:268:11
[Error.report] 
Exception { name: "NS_ERROR_MALFORMED_URI", message: "", result: 2152398858, filename: "https://myhost.example.com/reader/", lineNumber: 1, columnNumber: 0, data: null, stack: "i/<@https://myhost.example.com/reader/:1:1097\npostOpenWindow@https://myhost.example.com/reader/js/App.js?1601636202:174:9\nopenInNewWindow@https://myhost.example.com/reader/js/Article.js?1601636202:135:7\ninitHotkeyActions/this.hotkey_actions.open_in_new_window@https://myhost.example.com/reader/js/App.js?1601636202:953:24\nhotkeyHandler@https://myhost.example.com/reader/js/App.js?1601636202:824:24\ninitSecondStage/document.onkeypress@https://myhost.example.com/reader/js/App.js?1601636202:682:54\n" }
 
Object { message: "NS_ERROR_MALFORMED_URI: ", filename: "https://myhost.example.com/reader/", lineno: 1, colno: 0 }
App.js:558:12
xhrPost: 
Object { op: "rpc", method: "log", file: "https://myhost.example.com/reader/", line: 1, msg: "NS_ERROR_MALFORMED_URI: ", context: "i/<@https://myhost.example.com/reader/:1:1097\npostOpenWindow@https://myhost.example.com/reader/js/App.js?1601636202:174:9\nopenInNewWindow@https://myhost.example.com/reader/js/Article.js?1601636202:135:7\ninitHotkeyActions/this.hotkey_actions.open_in_new_window@https://myhost.example.com/reader/js/App.js?1601636202:953:24\nhotkeyHandler@https://myhost.example.com/reader/js/App.js?1601636202:824:24\ninitSecondStage/document.onkeypress@https://myhost.example.com/reader/js/App.js?1601636202:682:54\n" }
common.js:18:10
Uncaught 
Exception { name: "NS_ERROR_MALFORMED_URI", message: "", result: 2152398858, filename: "https://myhost.example.com/reader/", lineNumber: 1, columnNumber: 0, data: null, stack: "i/<@https://myhost.example.com/reader/:1:1097\npostOpenWindow@https://myhost.example.com/reader/js/App.js?1601636202:174:9\nopenInNewWindow@https://myhost.example.com/reader/js/Article.js?1601636202:135:7\ninitHotkeyActions/this.hotkey_actions.open_in_new_window@https://myhost.example.com/reader/js/App.js?1601636202:953:24\nhotkeyHandler@https://myhost.example.com/reader/js/App.js?1601636202:824:24\ninitSecondStage/document.onkeypress@https://myhost.example.com/reader/js/App.js?1601636202:682:54\n" }
reader:1
[Error.report] log response {"message":"HOST_ERROR_LOGGED"}

Event log: Nothing of any use that isn’t in any of the above.

check SELF_URL_PATH.

$ grep SELF config.php
//      define('_SKIP_SELF_URL_PATH_CHECKS', 1);
        define('SELF_URL_PATH', '//myhost.example.com/reader/');

Putting the schema back in fixed it.

(I’d finally updated and dragged in all the changes from the vulnerability fixes, presumably that’s what stopped it working.)

_SKIP_SELF_URL_PATH_CHECKS

i’m becoming convinced that this needs to be removed. are there any legit uses for it left, especially with compose setup? i can’t really think of any.