The folks at launchpad.net seem to get a real kick out of screwing things up for Opera. Using CSS code that only Opera understands, they forcefully enlarge the left offset of the navigation menus that are present on their subpages from the intended 20 pixels to 280 pixels. This causes the navigation menu to be displayed in front of the text.
Here's the relevant CSS code for your viewing pleasure:
div[id$="portlets"]{padding-left:280px !important}div[id$="portlets"]:not([class="xxx"]){padding-left:20px !important}@media all and (min-width:0px){div[id$="portlets"]{padding-left:280px !important}}
This UserJS script works around the problem by forcing the left offset back to 20px.
You will notice a minor flickering as the menu is moved to the correct position. This cannot be avoided (at least not easily).
Note: The launchpad.net site resides on a secure server so you must enable UserJS over HTTPS. This setting is disabled by default because of security concerns.
Download: launchpad.net-circumvent-Opera-targeting.zip
This script replaces my previous wdc.com menu fix contribution to the UserJS.org site.
The main items in the navigation menu on wdc.com contain images. When you direct the cursor over them, they may show a dropdown submenu. These submenus are not accessible if you move the cursor toward them at a normal speed. This problem occurs because there is a small gap between the main navigation menu items and the submenus.
According to the specification, images are "inline elements" by default and as such should have a descender space. Opera is one of the few mainstream web browsers that obey this specification. This descender space is the gap between the main navigation menu items and their submenus.
There are several possibilities to do away with the descender space via CSS depending on the situation. This UserJS script utilizes one of them.
The other problem on the wdc.com site is the language selection dropdown menu, situated above the navigation menu. There is also a gap here, but this problem occurs due to incorrect browser sniffing; Opera is believed to be Internet Explorer and as such gets styles which are meant to correct problems in Internet Explorer's Quirks Mode rendering engine.
This UserJS script makes sure the script at wdc.com thinks we're not Internet Explorer. Additionally, it identifies Opera as Mozilla and the version as 9.0. The reason for these extra measures which are not needed to make the language dropdown menu work is that the script on wdc.com does specific things for MSIE and Mozilla, so other portions of the site may be inaccessible to Opera users.
Thanks to xErath for the guidance with respect to the second problem.
Download: wdc.com-nav-lang-fix.zip
The top right navigation menu on wiki.ubuntu.com doesn't show as intended; all items except the last are displayed too high.
The culprit is the styling of the UL element that is used to format the navigation menu. It is set to display: inline. There is no need for this. The following UserJS file resets the display property of that UL element to display: block.
Download: wiki.ubuntu.com-menufix.zip
Note: The Ubuntu Wiki site resides on a secure server so you must enable UserJS over HTTPS. This setting is disabled by default because of security concerns.
Some 3rd party plugin installation tools may detect Mozilla's plugins folder but not Opera's. The intention of this script is to create an INF file which contains the necessary registry information to make these applications aware of Opera's plugins folder too. In other words: when the INF file is executed, those tools are led to believe that the Opera plugins folder is a Mozilla plugins folder. Multiple Opera installation folders are supported.
It was tested and found working for Adobe Shockwave Player (Shockwave for Director).
This script...
The Opera folders may have varying path depths, but they must reside under "Program Files" and the folder directly beneath "Program Files" must have the word "Opera" in its name.
Other important things to note...
This script was made to work on Windows 2000, Windows XP and Windows Server 2003 x86. Windows NT 4.0 may be supported as well but I can't test for that.
If you prefer to run the created INF file manually, right-click it and select "Install".
The following files are needed in your SYSTEM32 folder for the script to execute properly (they should be there by default):
USE AT YOUR OWN RISK!!!
Download: Opera plugins fix.zip