Firefox 8: Faster, by delaying tab loading

Short version: Preferences -> General -> "Don't load tabs until selected", now you can have hundreds of tabs "open" without slowing down your computer.

I like to keep many tabs "open" in Firefox.  I use a tree-based tab manager (Tree Style Tab view) that lets me build collapsible trees of tabs, built around a common theme.  Yay.  But having a tab open takes up memory and sometimes CPU (with Javascript in the background).  Bookmarks don't work for me, because they're an extra layer of management and "out of sight-out of mind" applies.  I just bookmark and forget forever, so instead I leave the tabs open until I have time to deal with each one.  Some are open forever, for good reason.



I used to use an extension called BarTab, which would allow me to delay the loading of a tab until I actually clicked it to visit it.  So, when I'd start my browser and it would restore all my tabs from my last sessions, they wouldn't load and thus save me a lot of memory.  Once I clicked on a tab, the page would actually load.  This was wonderful, but BarTab hasn't officially supported a version of Firefox since 3.x, and today we're on 8.  (I've been editing the extension to alter the version it supports, but that's fragile and not a good long term solution.)



Good news though!  Firefox 8 now supports on-demand tab loading!  I would post screenshots, but my interface is in German, so just follow these instructions if you need detail.  Elsewise, just go to Preferences, General, and with "restore tabs from last session" selected as your default home page, check the "Don't load tabs until selected" box.  Yay!

Fedora 16: Nice new features

Deliciously in Deutsch

Tablet support

One of my favourite new features in Fedora 16 and GNOME 3.2 is improved tablet support, complete with some programmability, under the System Settings menu.  There are more features to support, but at least the basic ones don't require text file editing anymore. :)



On-screen keyboard

There is even a nice on-screen keyboard under the accessibility menu, which is great if you have touch on your tablet PC.  :)  It even hides neatly in the notification tray.



Online accounts and privacy concerns

Something I'm wary of is the new Online Accounts manager, found in the user menu (top right).  Basically, you can log in once with GNOME to a web service provider like Google and it will share access to applications that request it.  A bit simpler than giving your login credentials to a dozen different programmes.  A bit safer in that respect.



But then there doesn't seem to be a facility to control which applications have access to that. I'd like to log in through GNOME, and then give permission to Evolution to just access my E-mail and Calendar, and give permission to Empathy to just access my contacts.  Perhaps this is restricted, and I have to find out before I use it, because I don't want just any application to go accessing my private data.

Fedora 16: "Oh no!" failure at log in (solution within)

I've just upgraded to Fedora 16, and it was an almost perfect upgrade except for one ugly problem.


Unlike my upgrade to Fedora 16 Beta, this upgrade of packages went well.  I used the preupgrade tool to download all the packages and let them update after a reboot: almost no input required.  However, when I went to log in to my system, I saw a useless error message:

"Oh no!  Something has gone wrong."

It then asks me to log out.  I quickly realised that nothing really seemed wrong.  I clicked on the full-screen error message and pressed alt-F4 to close it and continue working.  I didn't want to deal with this every time, so I figured out the source (method documented below):



The culprit is installed colour profiles from Fedora 15 causing a key component to crash invisibly in the background due to security policy issues.  Ugh.



Solution

On a terminal,

restorecon -r ~/.local/share/icc 

An idea situation would be to have random ICC colour profiles not cause this.



Problem Solving Method

• test a fresh account: does it have the problem?  No, so it must be my user's configuration.


• back up my configuration and then try resetting various parts to default until I can find the source of the problem.   


• With .config and .gnome2 reset, the problem persisted, so it must be something else


• Try resetting all configuration directories (/home/user/.somecfgdirname)




• alright, that worked, so it is in one of the . directories.




• I have 189 of them, so bisect my original configuration to narrow down its location




• Alright, a-m reset resolves the problem, so it's in there




• A quick scan and I see .local which seems relevant, as lots of applications store information in there.




• Testing my original configuration without my .local resolves the problem. 


• I don't want to get rid of everything in my .local




• Try removing .local/lib: problem still there


• Try removing .local/share: problem fixed


• Alright, which application is storing problematic files in .local/share?




• bisect again, it's in a-m


• bisect again, it's in h-m


• take a look, and icc, the colour profile configuration seems like a possible candidate




• Reset icc and bingo!  

Then feel stupid because I actually read about this very problem in Fedora 16's common bugs page (it's a wiki that has things added with work arounds until they are resolved).   However, I didn't think it was my problem because there it says that GNOME Shell fails, and I unfortunately knew that my GNOME Shell was still running, but just giving me an error message inexplicably. 



From the Fedora Project's common bugs page:

Starting GNOME Shell fails after upgrade from Fedora 15 with color profile installed

link to this item - Bugzilla: #741549


If you used the gnome-color-manager
tool to install a color profile for any of your hardware in Fedora 15,
then after upgrading to Fedora 16, you may not be able to log in to
GNOME Shell with SELinux enabled. Login will fail with the "Oh no!
Something has gone wrong" error screen that GNOME pops up if a component
is crashing repeatedly.



The issue is caused by gnome-settings-daemon
crashing when it encounters a color profile with an incorrect SELinux
context: the correct context for color profiles changed between Fedora
15 and Fedora 16, but the upgrade process does not re-label existing
profiles.




To resolve the issue, boot to a different desktop or to a console and run the command restorecon -r ~/.local/share/icc. After doing this, GNOME login should work correctly.

Problem solving



I like hunting and solving problems.   I like narrowing down causes, and combining bisection with intuition and existing knowledge to understand the source of such things.



Sadly, many users don't have the same knowledge.  They might not know where to start.  My Fedora 16 Beta installation problem, where it trashed my system partition, was potentially catastrophic but ultimately not a big deal because I could handle myself.  This ICC colour profile permissions problem is relatively simple, but thanks to an oblique error message, what could a "normal" user do?  It's stuff like this that prevents me from recommending an otherwise wonderful system to my friends.  I fear the problem is systemic.