Ah, I've forgot to add comment about when using gnome-shell.
Using gnome-shell is work for me.
This issue is only for weston including 2.0.0-1.fc26.x86_64.

I've also confirmed that using GDK_WINDOW_TYPE_HINT_POPUP_MENU as gtkTypeHint can handle clicking but cannot handle child menu on weston.
Using GDK_WINDOW_TYPE_HINT_UTILITY as gtkTypeHint can handle child menu but cannot handle on weston.

When using firefox-wayland-56.1-1.fc26.x86_64, I got same result to comment #0.

And I confirmed that keyboard events can be handled by popup menus and its child when using GDK_WINDOW_TYPE_HINT_UTILITY.

When settting ui.popup.disable_autohide as true, it works for me.
This Bug caused by wrong handling for ui.popup.disable_autohide on weston?

Or another way to re-enable to handle cliking event on weston as below:

Reoving !this._identityPopup.hasAttribute("noautohide") clause from https://dxr.mozilla.org/mozilla-central/source/browser/base/content/browser.js#7652 solves unhandled clicking issue on weston.
But both of ways seems to be unnatural for me.

Created attachment 1295729 [details]
Patch for to enable to handle clicking events in popup menu on weston.

Without this patch, I encountered not to be handled clicking events in popup menus on Weston even if weston 2.0.0.
With this patch, clicking events in popup menus works for me.

But I'm not fully understand why this patch enables to handle clicking events for popups.

It may be a regression from Bug 1466377 which updates the noautohide popups.

I just tested latest gecko-dev and weston-2.0.0-1.fc26.x86_64 and the bookmark example works for me. Do you still see that?

I also have gtk3-3.22.16-1.1.fc26.x86_64 installed.

(In reply to Martin Stransky from comment #9)
> I just tested latest gecko-dev and weston-2.0.0-1.fc26.x86_64 and the
> bookmark example works for me. Do you still see that?

Yes, I do.
I still see this issue on Fedora 26 and weston-2.0.0-1.fc26.x86_64.

And with the following prefs.js which contains any debugging purpose settings:


```
# Mozilla User Preferences

/* Do not edit this file.
 *
 * If you make changes to this file while the application is running,
 * the changes will be overwritten when the application exits.
 *
 * To make a manual change to preferences, you can visit the URL about:config
 */

user_pref("app.update.lastUpdateTime.addon-background-update-timer", 0);
user_pref("app.update.lastUpdateTime.background-update-timer", 0);
user_pref("app.update.lastUpdateTime.blocklist-background-update-timer", 0);
user_pref("app.update.lastUpdateTime.browser-cleanup-thumbnails", 1499739809);
user_pref("app.update.lastUpdateTime.experiments-update-timer", 0);
user_pref("app.update.lastUpdateTime.search-engine-update-timer", 0);
user_pref("app.update.lastUpdateTime.xpi-signature-verification", 0);
user_pref("browser.bookmarks.restore_default_bookmarks", false);
user_pref("browser.bookmarks.showMobileBookmarks", false);
user_pref("browser.cache.disk.capacity", 1048576);
user_pref("browser.cache.disk.filesystem_reported", 1);
user_pref("browser.cache.disk.smart_size.first_run", false);
user_pref("browser.cache.frecency_experiment", 3);
user_pref("browser.laterrun.bookkeeping.profileCreationTime", 1499739779);
user_pref("browser.laterrun.bookkeeping.sessionCount", 1);
user_pref("browser.laterrun.enabled", true);
user_pref("browser.migration.version", 48);
user_pref("browser.newtabpage.enhanced", true);
user_pref("browser.newtabpage.storageVersion", 1);
user_pref("browser.onboarding.notification.lastPrompted", "onboarding-tour-private-browsing");
user_pref("browser.pagethumbnails.storage_version", 3);
user_pref("browser.places.smartBookmarksVersion", 8);
user_pref("browser.safebrowsing.provider.mozilla.lastupdatetime", "1499739800458");
user_pref("browser.safebrowsing.provider.mozilla.nextupdatetime", "1499743400458");
user_pref("browser.search.countryCode", "JP");
user_pref("browser.search.region", "JP");
user_pref("browser.selfsupport.enabled", false);
user_pref("browser.slowStartup.averageTime", 19866);
user_pref("browser.slowStartup.samples", 1);
user_pref("browser.startup.homepage_override.buildID", "20170711105538");
user_pref("browser.startup.homepage_override.mstone", "56.0a1");
user_pref("browser.uiCustomization.state", "{\"placements\":{\"widget-overflow-fixed-list\":[],\"addon-bar\":[\"addonbar-closebutton\",\"status-bar\"],\"PersonalToolbar\":[\"personal-bookmarks\"],\"nav-bar\":[\"urlbar-container\",\"search-container\",\"bookmarks-menu-button\",\"downloads-button\",\"home-button\",\"sidebar-button\",\"pocket-button\",\"screenshots_mozilla_org-browser-action\"],\"TabsToolbar\":[\"tabbrowser-tabs\",\"new-tab-button\",\"alltabs-button\"],\"toolbar-menubar\":[\"menubar-items\"]},\"seen\":[\"pocket-button\",\"webcompat-reporter-button\",\"developer-button\",\"webide-button\",\"screenshots_mozilla_org-browser-action\"],\"dirtyAreaCache\":[\"PersonalToolbar\",\"nav-bar\",\"TabsToolbar\",\"toolbar-menubar\"],\"currentVersion\":6,\"newElementCount\":0}");
user_pref("datareporting.policy.dataSubmissionPolicyAcceptedVersion", 2);
user_pref("datareporting.policy.dataSubmissionPolicyNotifiedTime", "1499739804495");
user_pref("e10s.rollout.cohort", "unsupportedChannel");
user_pref("experiments.activeExperiment", false);
user_pref("extensions.blocklist.pingCountVersion", 0);
user_pref("extensions.databaseSchema", 21);
user_pref("extensions.e10s.rollout.hasAddon", false);
user_pref("extensions.e10sBlockedByAddons", false);
user_pref("extensions.e10sMultiBlockedByAddons", false);
user_pref("extensions.getAddons.databaseSchema", 5);
user_pref("extensions.lastAppVersion", "56.0a1");
user_pref("extensions.lastPlatformVersion", "56.0a1");
user_pref("extensions.pendingOperations", false);
user_pref("extensions.shield-recipe-client.api_url", "https://normandy.cdn.mozilla.net/api/v1");
user_pref("extensions.shield-recipe-client.dev_mode", false);
user_pref("extensions.shield-recipe-client.enabled", true);
user_pref("extensions.shield-recipe-client.logging.level", 50);
user_pref("extensions.shield-recipe-client.run_interval_seconds", 86400);
user_pref("extensions.shield-recipe-client.startup_delay_seconds", 300);
user_pref("extensions.shield-recipe-client.user_id", "");
user_pref("extensions.systemAddonSet", "{\"schema\":1,\"addons\":{}}");
user_pref("extensions.webextensions.uuids", "{\"screenshots\":\"4c99ee95-d223-453f-9384-7abbced7ecb2\"}");
user_pref("gecko.handlerService.migrated", true);
user_pref("media.gmp-gmpopenh264.abi", "x86_64-gcc3");
user_pref("media.gmp-gmpopenh264.lastUpdate", 1499739815);
user_pref("media.gmp-gmpopenh264.version", "1.6");
user_pref("media.gmp-manager.buildID", "20170711105538");
user_pref("media.gmp-manager.lastCheck", 1499739806);
user_pref("media.gmp.storage.version.observed", 1);
user_pref("network.cookie.prefsMigrated", true);
user_pref("pdfjs.migrationVersion", 2);
user_pref("pdfjs.previousHandler.alwaysAskBeforeHandling", true);
user_pref("pdfjs.previousHandler.preferredAction", 4);
user_pref("places.history.expiration.transient_current_max_pages", 104858);
user_pref("plugin.disable_full_page_plugin_for_types", "application/pdf");
user_pref("signon.importedFromSqlite", true);
user_pref("toolkit.startup.last_success", 1499739770);
user_pref("toolkit.startup.recent_crashes", 1);
user_pref("toolkit.telemetry.previousBuildID", "20170711105538");
user_pref("toolkit.telemetry.reportingpolicy.firstRun", false);
```

When setting ui.popup.disable_autohide as true, it works for me.

And I also use gtk3-3.22.16-1.fc26.x86_64.

Comment on attachment 1295729 [details]
Patch for to enable to handle clicking events in popup menu on weston.

I've noticed that this patch causes SEGV on a key press.
This approach seems to be wrong.

This bug appears to have been reported against 'rawhide' during the Fedora 27 development cycle.
Changing version to '27'.

This message is a reminder that Fedora 27 is nearing its end of life.
On 2018-Nov-30  Fedora will stop maintaining and issuing updates for
Fedora 27. It is Fedora's policy to close all bug reports from releases
that are no longer maintained. At that time this bug will be closed as
EOL if it remains open with a Fedora  'version' of '27'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, simply change the 'version' 
to a later Fedora version.

Thank you for reporting this issue and we are sorry that we were not 
able to fix it before Fedora 27 is end of life. If you would still like 
to see this bug fixed and are able to reproduce it against a later version 
of Fedora, you are encouraged  change the 'version' to a later Fedora 
version prior this bug is closed as described in the policy above.

Although we aim to fix as many bugs as possible during every release's 
lifetime, sometimes those efforts are overtaken by events. Often a 
more recent Fedora release includes newer upstream software that fixes 
bugs or makes them obsolete.

Fedora 27 changed to end-of-life (EOL) status on 2018-11-30. Fedora 27 is
no longer maintained, which means that it will not receive any further
security or bug fix updates. As a result we are closing this bug.

If you can reproduce this bug against a currently maintained version of
Fedora please feel free to reopen this bug against that version. If you
are unable to reopen this bug, please file a new report against the
current release. If you experience problems, please add a comment to this
bug.

Thank you for reporting this bug and we are sorry it could not be fixed.

This issue has been fixed and is no longer present in current releases of Firefox.