When sharing access to Stream videos with specific users, adding new users in the 'Permissions' area doesn't share the content...the user still has to click 'Apply.' If the user scrolls down on the page, the 'Cancel' and 'Apply' buttons become hidden. Consider making these buttons always appear at the top of the page (similar to a frozen row in Excel) and/or relocating the 'Apply' button (possibly below the 'Details' and 'Permissions' areas) for a more intuitive UI across device types and screen sizes.
Initial view:
Initial view with Cancel and Apply buttons at top of view
Browser scrolling hides 'Apply' and 'Cancel' buttons...
Cancel and Apply buttons hidden by browser scrolling