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Looks interesting. I'm not sure about this error page? @rullzer @ChristophWurst
Do you have Opera Turbo enabled? If so could you try without?
At first I thought it was just a bug in the gallery app, but it also happens in the webview.
If this issue turns out to be true, this one would be a REAL "show-stopper" to prevent me from upgrading to NC16!
What phone are you actually using and what browser? All works as expected here in chromium and firefox mobile.
@skjnldsv @ChristophWurst @juliushaertl any of you in a position to test opera?
Can confirm the bug on:
OnePlus 3, Android 8.0.0, Chrome
Moto G5, Android 8.1.0, Chrome and Firefox
Huawei P9 lite, Android 7, Chrome and Firefox
Scroll only works in the yellow Area:

Bug confirmed on BQ Aquaris X Pro, Android 8.1, Firefox Mobile
Bug confirmed on MotoG4 Play, Android 7.1 and Lenovo TAB2 A10-70F, Android 6, Chrome and Firefox
Edit: Some folders without write access work as expected.
Bug confirmed on FF for Android
I was able to reproduce the issue using chrome dev tools in mobile view.
The behavior is caused by the css class .ui-draggable-handle that has "tourch-action" set to "none".
If i remove it scrolling works as expected. Also "touch-action" is not disabled on the first column with the checkboxes. (see comment made by @Gatak )
If you remove this property scrolling works:

For a permanent solution further investigation is required to find out why "touch-action" has been added.
My uess is the move of our jquery library into our webpack config? @ChristophWurst
Maybe we added a new css change from one of our dependency? this seems related to jquery-ui (yeaaaah) :)
My uess is the move of our jquery library into our webpack config? @ChristophWurst
The jquery libs haven't changed much with the webpack bundling. But we updated jquery-ui a bit: https://github.com/nextcloud/server/pull/11718
Yep, this is it: 1.12.1 - 1.11.0-beta.1
https://github.com/jquery/jquery-ui/commit/28310ff55f062199fb2f187ea13d3561a879aea8#diff-e8b8fd48040d8abc0af402d340bb1b05R11
Fix in #15462
Most helpful comment
Yep, this is it: 1.12.1 - 1.11.0-beta.1
https://github.com/jquery/jquery-ui/commit/28310ff55f062199fb2f187ea13d3561a879aea8#diff-e8b8fd48040d8abc0af402d340bb1b05R11