I need check your page to find what’s element block the filter. Please leave the page URL, thanks!
Also when I manage to open categorise in a new tab grid layout disappears. Posts are appearing one by one showing every detail of the post such as date-author info. Is there a way to hide or prevent it, or maybe set each categories’ page with grid layout?
The new tab opened page is archive page, so you need create a page with template for each sub-category. Use a re-direct plugin to re-direct default url to new page url.
Or use a plugin to disable mouse right button like: https://wordpress.org/plugins/right-click-disable-orignal/