I am running 64 bit Ubuntu 12.04 LTS. Having a need to type both classical Greek and modern Thai text in addition to standard English, I loaded iBus using the Ubuntu Software Center.

I quickly discovered that, because the base iBus package doesn't include support for either of those languages, I also needed to load the ibus-m17n_1.3.3-1.debian package in order to have access to the character sets for each of the aforementioned languages.

Things seem to work well enough for base characters, but no accents or those sorts of characters work, which essentially renders the iBus capability useless for actual work. When using Thai for example, none of the supported vowels or accents (i.e. supported characters is the unfortunate term for those characters that appear over or below the character they modify) seem to be available. Sometimes when I type the appropriate key, I think I can see the correct character flash momentarily, but then it and the character I've attached it to both disappear. I've attempted to adjust the leading and line spacing in those apps that have that capability (e.g. LibreOffice), but this makes no difference (which I don't believe it should, since there is plenty of vertical spacing built in to the fonts). Vowels that are independent characters work just fine.

I don't believe the issue is related to any of the fonts I am using, since all the other characters (consonants and unsupported vowels) appear as expected. So my questions are:

#1) What am I missing? I searched around on the web for some sort of iBus user guide and, although there are lots of technical discussions, I was unable to locate anything that discusses the basics of using it. Indeed, the very few short blurbs I've come across seem to be incorrect - for example, to rotate through multiple foreign keyboards, the Alt+Shift+L command is called for, but I've found that Alt+Shift works just fine and doesn't add whatever character is assigned to the 'L' key.

#2) Is there some way short of looking at an entire font in a font editor to determine if any particular font contains sections for a specific character set (e.g. Greek or Thai)?

#3) What is it that determines which font is used for a particular alphabet when using iBus? For instance, if my base font is set to Garamond and I switch to Greek, the font used is still Garamond, which makes sense, since that font contains Greek characters. But if I switch to Thai, the font that is used is 'Lohit Hindi,' which seems strange to me for two reasons.

The first reason is that 'Lohit Hindi' is primarily a Hindi font - and a sans serif to boot (clashes with the serif Garamond) - and I have several more appropriate Thai fonts available. I can't find anything in the Preferences dialog to alter this.

The second reason is that when I pull up the character map (in LibreOffice, [Insert-Special Character]), the 'Lohit Hindi' font doesn't seem to have any mappings for the Thai character set. So, where are the characters coming from??

Any pointers, guidance, or assistance would be quite helpful ...