QA in sidebar and popup window

[A.S.]

One of the most popular question asked by new users is: How to add website on sidebar?
And the answer is: No way. But in Vivadli, Firefox and old Opera you can do it, you can do it with WebPanel (add-on) in new Opera, but you can not just add website in MX sidebar. Many users ask about it many years, but where is this feature?

A few months ago I tried to solve this problem by using Google Bookmarks. But you need Google account to work with this and this service does not have mobile version (on desktop). So it looks not so cool as I want. So... This is not real solution of the problem.

     

A few days ago I thought of a new possible solution: just use build-in QA. So I tried to make test version of extension, which will add QA in sidebar and in popup window. This is not perfect solution because QA is too big for sidebar. But you don't need any other account, this is just your QA in sidebar. Just add a page with mobile websites there and you will not need other simple sidebar addons. 

     

I just use mx://newtab as URL for sidebar and popup windows. It works. Not ideal, but works. 
I have only one problem: different addresses in different version of browser. The mx://newtab works in MX 4.9. In MX4 I have to use about:blank, but it does not work and I can not understand why. Any ideas? MX5 use website as QA. But in the last versions they add offline. Does it mean that QA in MX5 has special internal address? Do you know what?

P.S.
If you know cool website which will be look better in sidebar winow, just tell.