User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; pl; rv:1.8.1.11) Gecko/20071127 Firefox/2.0.0.11 Mnenhy/0.7.5.0 Build Identifier: HOME SP2 PL When I enable Caps Lock and try to enter for polish character 'Ą' I get 'ą'. The same behavior I get for all polish national characters. I observed this bug in Thunderbird 2.0.0.9, Firefox 2.0.0.10 and 2.0.0.11. Also I found that this bug was submitted to Thunderbird with Bug 377411. Reproducible: Always Steps to Reproduce: 1. Open new message in Tunderbird or go to address field or any other field editor in Firefox. 2. Disable Caps Lock. 3. Enter right alt + a 4. The result is 'ą' as expected. 5. Enable Caps Lock. 6. Enter right alt + a 7. The result is 'ą' but expected was 'Ą'. The workaround is to entering this uppercase characters with Caps Lock disabled using shift + right alt combination.