Steps to reproduce the issue

• Install a new site.
• Install an extension with a custom Dashboard, e.g. https://www.akeeba.com/download/arsdev/7-1-0-dev202209271443-revc1215dcb.html

TEST 1

• Go to System, Global Configuration, Site.
• Set Unicode Aliases to No (that's the default).
• Click on Save & Close.
• Go to extension's dashboard (e.g. Components, and click the dashboard icon next to Akeeba Release System)

TEST 2

• Go to System, Global Configuration, Site.
• Set Unicode Aliases to Yes.
• Click on Save & Close.
• Go to extension's dashboard (e.g. Components, and click the dashboard icon next to Akeeba Release System)

Expected result

Test 1: The dashboard is shown
Test 2: The dashboard is shown

Actual result

Test 1: The dashboard is NOT(!!!) shown
Test 2: The dashboard is shown

System information (as much as possible)

Irrelevant.

Additional comments

This is yet another blatant bug in Joomla 4 which is trivial to spot and fix — if someone actually uses the Joomla 4 features ?

The problem lies in

However, what stringURLSafe does depends on the “Unicode Slugs” setting in Global Configuration ??

When that setting is No the underscore is converted to a dash, therefore the module position for this dashboard is cpanel-com-example-something.

When that setting Yes the underscore remains as is, therefore the module position for this dashboard is cpanel-com_example-something.

Since a module cannot be published in two positions at the same time the Dashboard breaks depending on the Global Configuration “Unicode Slugs” setting.

You do not see that with core dashboards because Joomla cheats when it comes to itself!. Instead of using component-specific dashboards it uses hardcoded dashboard names which do not include the com_ prefix or a dot, they just contain lowercase characters a-z without diacritics. When this happens, going through stringURLSafe returns the string verbatim, therefore Joomla's cheating dashboards always work.

Proposal

Right now, there is not one valid module position to use with component-specific dashboards. The only reasonable solution is to replace

$position = ApplicationHelper::stringURLSafe($dashboard);

with

$position = \Joomla\CMS\Filter\OutputFilter::stringUrlUnicodeSlug($dashboard);

This way we will have predictable dashboards which always use the module position format cpanel-com-example-something.

Tagging @laoneo because his bug report in my repo led me to discover the root cause of this issue (as you may have guessed, being Greek I use Unicode Slugs on my multilingual dev site…) and because he's in the leadership so he can make a decision about how to best fix this.