'i' and 'I' letters are not writing with Turkish keyboard

Hi; I'm using Ubuntu 16.04 x64. I installed Qt 5.8 and Qt Creator 4.2.1. I'm trying to set name of project or I'm trying to write 'i' and 'I' letters on editor. But when I pressed 'i' or 'I' keys, they are not writting. I installed Qt Creator 4.2.1 on Windows 10 Home. I can write 'i' and 'I' letters. Then I installed Oracle VirtualBox on Windows 10 Home and I installed Ubuntu 16.04 x64. I installed Qt Creator 4.2.1 on VirtualBox, but result is same. I can't write 'i' and 'I' letters with Turkish Q Keyboard. I think this is a bug. (i = Alt + 105 and I = Alt + 73)