Using multiple tabs with Virtualmin

I have lost the ability to use multiple tabs with Virtualmin.

When viewing my server logs I will typically go Webmin > System Logs then ctrl+click View of each of the logs i want to look at. Each of the logs will open in a new tab and I can then go through them and check for anything interesting. It is handy to have them in different tabs so i can quickly and easily check back and forth.

Similarly sometimes I will open and existing server config in one tab and copy elements from it into another tab.

The point being, using tabs in very handy!

Have multiple browser tabs been removed in the "Authentic Theme ", is it a bug or is my system to blame? Currently opening a tab give me a blank page and a js error “Uncaught TypeError: Cannot read property ‘contentWindow’ of undefined”