Error: Set Custom Permissions in Admin CP

[ShineCero]

I tried looking through the forum, but haven't seen anyone talk about this. There's an issue when clicking "Set Custom Permissions" under Forum Managment, the modal does not show up and instead, regulated to the bottom of the page. Furthermore, the sliding bar of the browser disappears, thus, cannot move the site up or down unless I refresh the page.

How can I resolve this? 

Thanks!

[Ikerepc]

Have you tryed using another browser and / or entering site from another device?

[ShineCero]

Yes. I used two different browsers and another device and it still shows the same issues when clicking "Set Custom Permissions" under Forum Management.

[MonsteR_X]

What is your MyBB virsion?

[ShineCero]

The MyBB version is set at 1.8.14.

[.m.]

if MyBB forum is recently upgraded then
some changes are required in the templates & style css.
basically javascript & modal popup related codes need modifications.

Visit your Admin Control Panel, then go to Templates & Style > Templates > Find Updated Templates.
This will show you a list of all the templates that have changed during the upgrade.

You can either revert these templates to their default - meaning all the changes you've made to it will be removed
- or you can see a Diff Report which will show you exactly what's changed. If you have a custom theme installed,
it is probably best that you look at the Diff Report and apply the changes you need.

for the style adjustments see this post

[ShineCero]

Thank you! I managed to solve that issue with the links you provided