Add that number to the end of "#stabsCell" and set it to display none to get the following:

#stabsCell1111111 { display: none; }

Add this bit of CSS to your custom css (Control Panel > Custom HTML & Script > Custom CSS > CSS Additions to Standard)

If you are using side tabs or want to use code instead, then use this script to hide the tab. Replace the number in red with the tabID.

Add this code to your custom script (Control Panel > Custom HTML & Script > Custom Javascript/JQuery > Document Ready Event).

// This will remove a side navigation link.
$('a.ActiveDiv[href*=1111111]').parent().hide();

// This will remove a tab in a static image type nav bar
$('a[href*=1111111]').closest('td[id^=stabsCell]').hide();

// This will remove a tab in a Dynamic image type nav bar
$('#straightBarWrapperInnerTable a[href*=1111111]').parent().hide();