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I am running Ubuntu 12.04 (almost default install regularly updated) Unity interface on ASUS X53U (AMD Brazos Dual Core C60 with 2GB RAM).

On launching Thunderbird and Firefox, the application dims and the cursor changes to wait mode. In case of Thunderbird, this is most pronounced with the wait time of up to a minute.

Memory status checked with free indicates around 500MB of free memory on such occasions. The OS is stable and I can switch to a different work-space, etc.

What could this be? Is this something normal?

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why don't you launch from the command line and see what it does, and if any flags are raised? – kmassada Oct 9 '12 at 13:44
It would be interesting to see if this happens with other applications that need to connect to the internet on startup. The obvious thing is that they are waiting for something. Whether they are fighting for the processor (scheduling time) or are waiting for the internet to become available is left to see yet. – Anthony Oct 10 '12 at 15:50
@PranitBauva Reinstalling won't do anything to solve his problem – Jorge Castro Oct 10 '12 at 22:16
@kmassada, tried launching it from terminal. There were no messages/ flags there. – deshmukh Oct 11 '12 at 6:24
@Anthony, could you suggest a way to check the bandwidth bottleneck? – deshmukh Oct 11 '12 at 6:36
up vote 6 down vote accepted

Why dimming?

The window dims because of a compiz setting , which dims the windows of programs which are not responding.

You can change the setting, if you have compizconfig-settings-manager installed.
Open it and go to Fading Window plugin. There is a settings named Dim unresponsive windows. Uncheck the setting if you don't want the dimming. But I don't recommend it, since it tells you which program is not responding.

enter image description here

Why Not responding?

The application may seem to be not responding while starting up sometimes. Mostly it happens when it does some background activities, such as fetching settings, loading files and trying to connect to the Internet etc.

I think, the most likely cause in your case is, You get large number of new messages in your email account everyday and thunderbird was trying to fetch those emails. But It is not a big problem since it quickly becomes responsive after the operation. It may also related with your Internet connection speed, which may be slowing down fetching and syncing information with your email account.

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Applications "dim" when they are busy like loading from disk. This is common on slower computers where applications might be competing for resources, or launching a bunch of applications at once.

This is normal on lower performance Notebooks. You might want to consider using a lighter desktop like Lubuntu or Unity 2d:

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could there be any tests to pinpoint the problem? As I mentioned, free shows memory available. That said, I will try Unity 2D (Easier) and LXDE (after I install it), and will let you know. – deshmukh Oct 11 '12 at 6:22

I have experienced similar issues, but mostly with Thunderbird.


Why is Thunderbird pegging a core at 100%?

Try disabling Thunderbird add-ons, as you (like me) are probably not using them anyway.

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