I can confirm that this issue is present in Chrome (ver. 25.0.1364.152 m). I also found that files (Startup2_all.js.zgz and NewWindow_all.js.zgz) that were affected (bug 58569) in Zimbra 8.0.2 FOSS 64bit contains fix for mentioned bug. So it means that this is something different - maybe in Zimbra 8 other files are responsible for that function? I will reopen (if possible) this bug with link to this post.
Please, do something quickly. The problem is very annoying, cant work on a different browser than Chrome.
On Mac OS X Mountain Lion and latest Chome no such issue - this seems to be a Chrome Windows version bug. This is probably because of cmd / ctrl keys difference in Apple hardware family.
So what I did to solve the problem:
1. From TinyMCE project page I downloaded tinymce_3.5.8.zip You can download it from here: https://github.com/tinymce/tinymce/downloads
2. After unpacking I found tiny_mce_src.js in tinymce_3.5.8/tinymce/jscripsts/tiny_mce folder.
3. I renamed tiny_mce_src.js to TinyMCE_all.js. Take care on last '.' after js - it is important.
4. I gzip-ed this file (gzip -S zgz TinyMCE_all.js.). You should have TinyMCE_all.js.zgz file after this operation.
5. I upload TinyMCE_all.js.zgz to /opt/zimbra/jetty/webapps/zimbra/js folder. Before that please make copy of original file.
6. After restarting Chrome browser Alt-a is now ą :) (In some situations it is good idea to first clear Chrome cache)
I did not check it on version 8.0.6 but it should work.
Hope this will help :)
Your solution is working! Great job! I have made it on Zimbra FOSS 8.0.6. and it's working.
Once again many thanks for your support.