Iphone

Please keep an eye on this blog entry - it will be updated as new information comes to light.
There are several problems being faced by users of IE7 related to tabbed browsing.

1. The option "open in new tab" is missing from the context (right click) menu;
2. The tab band is missing completely;
3. Sometimes third party toolbars may not appear, or seem to appear and disappear at will;
4. Sometimes links will open in new windows, even when all options are set to tabs only.

"Open in New Tab" context menu item is missing - Example: Google toolbar
The most commonly used add-in that will make the context menu item "open in new tab" disappear is the Google toolbar. Google have been informed of the problem, which occurs because the Google software overrides IDocHostUIHandler and then loads the old IE6 menu resources out of a file called shdoclc.dll.
Resolving the missing "open in new tab" and other interface problems
It should be noted that Google and Adobe are not the only products to cause problems. The best diagnostic test to confirm third party involvement in your problems is to run IE7 in no add-ons mode. You will find instructions on how to do this at this URL:
Known issues - Internet Explorer 7.
If your problem(s) go away it is simply a matter of disabling all add-ons, then enabling them one at a time, testing as you go, to work out which one is causing problems for you.
It should be noted that the middle click and Ctrl click should continue to work even if the "open in new tab" context menu is missing - if that is an acceptable solution for you until the problematic third party software is updated, then that's great. If not, you will have to consider uninstalling or disabling the problem software.
Tab band is missing completely
There is are no known third party add-ins that cause this problem. First, make sure you that you are not using Classic display mode. If you are, switch to standard XP display mode. This should make the tabs appear and then you can switch back to normal mode.
If that doesn't help, then invariably the cause is a damaged installation. In short, there are two files involved - xmllite.dll and ieui.dll (ieui.dll is also used by Quick Tabs).
xmllite.dll and ieui.dll should both be in %windir%\system32.
Troubleshooting steps - missing tab band:

1. Ensure xmllite.dll and ieui.dll are in %windir%\system32. If xmllite.dll is missing download and install the XMLLITE update mentioned at the end of this article. If ieui.dll is missing you should uninstall IE7, reboot twice and reinstall again, this time following all the instructions above.

Edit: regsvr32 commands removed.
If you are still having problems close Internet Explorer and run gpedit.msc. Navigate to User Configuration --> Administrative Templates --> Windows Components --> Windows Explorer --> Force Classical View. Set Force Classical View to "Disable".
Note there is also a "Turn off Tabbed Browsing" option at Navigate to User Configuration --> Administrative Templates --> Windows Components --> Internet Explorer.
If IE7 still does not have a tab band after restarting go to the following web page and install the appropriate version of the xmllite update package available at this URL:

The XmlLite update package is available for 32-bit versions of Windows XP with Service Pack 2
It should not be necessary to uninstall IE7 before installing the xmllite update package. If your issue is not resolved after installing the update package (and rebooting twice), you can try uninstalling IE7, rebooting twice, then installing again, making sure you follow the pre-installation advice here:
Known issues - Internet Explorer 7
Third party toolbars may not appear, or seem to appear and disappear at will - example: Adobe Professional toolbar
The Adobe Professional will only display when viewing the first tab. If any other tabs are opened, the toolbar does not load and can not be reactivated. Adobe have been informed. In this example both the toolbar and explorer bar fail in the very first call into IObjectWithSite::SetSite() on secondary tabs, but in new windows it works fine. "Open in new tab" does not seem to be affected.
Sometimes links will open in new windows, even when all options are set to tabs only
This happened to me as soon as I installed the Messenger Plus! Live Sponsor Program for testing. The problem disappeared as soon as the Sponsor Program was uninstalled.
Therefore, you must check for adware and malware, and for third party applications that may be causing a problem. The MP!L Sponsor Program generates some advertising pop-ups that are sometimes different to the norm - no addressbar, no status bar, they can't be resized and right click doesn't work. I can only assume that whatever the Sponsor Program does to override my "no windows, tabs only" settings is also interfering with IE7's overall ability to open hyperlinks and pop-ups only in tabs.
These are my settings - they did not work when the MP!L sponsor program was installed - hyperlinks were opened in new windows instead of tabs:

My grateful thanks to Tony, Tony, Chris and John on the IE team for their input and guidance about these issues