I uploaded a screen here it is

Why nobody answers ?

Can you resize this pop-up if you press Alt+Space to open its system menu?

You can check for problems caused by a corrupted localstore.rdf file.

• http://kb.mozillazine.org/Corrupt_localstore.rdf
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

Yes i can resize it, but when i close it gets back to normal. I tried with deleting localstore.rdf form profile folder but nothing happens ;\

The screenshot shows a window that is much smaller then it should be, so there is definitely something wrong here.

Does starting Firefox in Safe Mode has any effect?

• Help > Restart with Add-ons Disabled

• https://support.mozilla.org/kb/Safe+Mode

No its the same with safe mode

I've installed the Bulgarian Firefox version and I see the same small Clear Recent History window.

The DOM Inspector shows a width of 14em and that is really too small compared to what I get with the en-US version (width: 34em).

Add code to the userChrome.css file below the default @namespace line to increase the default width.

• http://kb.mozillazine.org/userChrome.css

The customization files userChrome.css (user interface) and userContent.css (websites) are located in the chrome folder in the Firefox profile folder.

• http://kb.mozillazine.org/Editing_configuration

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"); /* only needed once */

#SanitizeDialog {width: 34em !important;}

See:

• view-source:chrome://browser/locale/sanitize.dtd

Sounds that something got wrong here and maybe a bug should be filed:

<!-- LOCALIZATION NOTE (dialog.width2): width of the Clear Recent History and
     Clear History on Shutdown dialogs.  Should be large enough to contain
     the item* strings above on a single line.  The column width should be set
     at half of the dialog width. -->

<!ENTITY dialog.width2                 "14em">   (shouldn't this be at least 28em ?)
<!ENTITY column.width2                 "14em">

The sanitize.dtd in the en-US locale:

<!-- LOCALIZATION NOTE (dialog.width2): width of the Clear Recent History and
     Clear History on Shutdown dialogs.  Should be large enough to contain
     the item* strings above on a single line.  The column width should be set
     at half of the dialog width. -->
<!ENTITY dialog.width2                 "34em">
<!ENTITY column.width2                 "17em">

Thank you for your answer. I couldnt find the chrome folder so i created one and put userChrome.css file then i insert your code

uploaded a picture of the code is this correct ?

There seems to be more wrong looking at the bugs that have been filed:

• https://bugzilla.mozilla.org/buglist.cgi?product=Mozilla%20Localizations&component=bg%20%2F%20Bulgarian&resolution=---

Only these two lines need to be in the userChrome.css file:

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"); /* only needed once */

#SanitizeDialog { width: 34em !important; }

Thank you very much for your help and spended time :)