New minimal testcase now available at https://raw.githubusercontent.com/anaran/import/9bf3e184ad4bfffb4b5377f0e03ff64018cf6164/shadowy_testcase.js Just run it in a Scratchpad on a newly opened tab (Ctrl+T) or just about:blank. Use Scratchpad in WebIDE to remotely debug on Android device via Wifi or USB. Try typing in the top or bottom elements. No characters get inserted.

(In reply to Edgar Chen [:edgar] from comment #1) > Created attachment 8934063 [details] > bug_1421831_test.html I could reproduce this without custom elements, it looks like a shadow dom issue. But AFAIK, we are moving shadow dom implementation from v0 to v1, I am not sure if it is worth to take a look at this issue in current stage.

Thanks Edgar for the minimal test case. This is still reproducible with Shadow DOM v1, we'll get back to this once the implementation is complete.

(In reply to Edgar Chen [:edgar] from comment #2) > (In reply to Edgar Chen [:edgar] from comment #1) > > Created attachment 8934063 [details] > > bug_1421831_test.html > > I could reproduce this without custom elements, it looks like a shadow dom > issue. But AFAIK, we are moving shadow dom implementation from v0 to v1, I > am not sure if it is worth to take a look at this issue in current stage. Hi Edgar, I do my tests using permutations of Services.prefs.setBoolPref('dom.webcomponents.enabled', true) Services.prefs.setBoolPref('dom.webcomponents.customelements.enabled', true) and reloading the browser tab after that. Q: AFAIK v0 means createShadowRoot and v1 attachShadow, correct? Q: Right now Services.prefs.setBoolPref('dom.webcomponents.enabled', true) seems to make both available at the same time, correct? I am trying to use customElements as much as possible in development, especially scoped CSS, and would be thankful for any workarounds. What would be the best medium to ask questions like these, since this bug is surely not it :-?

(In reply to Adrian Aichner [:anaran] from comment #4) > Hi Edgar, I do my tests using permutations of > Services.prefs.setBoolPref('dom.webcomponents.enabled', true) > Services.prefs.setBoolPref('dom.webcomponents.customelements.enabled', true) > and reloading the browser tab after that. > > Q: AFAIK v0 means createShadowRoot and v1 attachShadow, correct? v0 uses createShadowRoot and v1 uses attachShadow. But there's more difference detailed in https://hayato.io/2016/shadowdomv1/ > Q: Right now > Services.prefs.setBoolPref('dom.webcomponents.enabled', true) > seems to make both available at the same time, correct? It was, but not after bug 1400762 landed in 59. > I am trying to use customElements as much as possible in development, > especially scoped CSS, and would be thankful for any workarounds. > > What would be the best medium to ask questions like these, since this bug is > surely not it :-?

(In reply to Adrian Aichner [:anaran] from comment #4) > What would be the best medium to ask questions like these, since this bug is > surely not it :-? dev-platform mailing list or irc content channel would be a good medium to ask questions.

This should be the same as bug 1066965.