Can not use i,ı,İ or I keys in Webapps

First of all, I am an Ubuntu 14.04 user and my locale is Turkish. This bug is not related only Facebook app, but all other apps.
When I try to use a Webapp with Turkish locale I can not use i,ı,I or İ keys as described in the summary.

When I start the app in terminal I see those errors:

"Qt Warning - invalid keysym: I"
"Qt Warning - invalid keysym: i"
...
"Qt Warning - invalid keysym: Greek_EPSILON"
...
"Qt Warning - invalid keysym: Greek_ETA"
...
"Qt Warning - invalid keysym: Cyrillic_I"
...
"Qt Warning - invalid keysym: Cyrillic_i"
...
"Qt Warning - invalid keysym: Ukrainian_i"

and some other errors. If I use LC_ALL=C with those apps errors vanish and I can use the keys.