When you open the newtab (the + button) what do you want to be displayed?

With Firefox 41 (and higher), it's no longer possible to customize the page shown in a new tab via changing the preference browser.newtab.url in about.config. Because of the fact that hijackers abused the preference in the past, Mozilla decided to remove it (see bug 1118285). Fortunately, by removing it, Mozilla also introduced a new API to bring this functionality back to life as an add-on. This add-on allows the user to choose a certain page in a new tab.

New Tab Override (browser.newtab.url replacement) https://addons.mozilla.org/en-US/firefox/addon/new-tab-override/

This is also available using Classic Theme Restorer (Customize Australis) {web link} Restore squared tabs, appmenu, add-ons bar, small button view and more on Australis UI (Windows/MacOSX/Linux + Fx 29+).

Hi

Is this about tabs you (re)open automatically on the next Firefox start via Session Restore? If there is no URL in the location/address bar on a tab then you will see a blank (about:blank) page.

sorry if my explanation not enough, I meant when I click on a link(Ctrl+Mouse Click), a new tab opened, firefox tried to enter it but if the net connection lost, Url of page redirect to "about: blank".

When I lose the internet, the address of where I want to go is in the address bar, but I get a warning message. Not about:blank

Why are you losing the internet?

I don't know, may my ISP provider not good company, anyway this problem exist.

Have you tried rebooting   ?
And maybe you could contact your internet provider   ?

rebooting yes, but i don't think so this is regarding my provider.

thanks