Qt Virtual Keyboard bug in Lubuntu

[peaceblackhair]

I'm trying to active a Qt Virtual Keyboard whenever user touch a any textinput.

I Can call Qt Virtual Keyboard like this command :

os.environ["QT_IM_MODULE"] = "qtvirtualkeyboard"

In Ubuntu and Xubuntu Virtual Keyboard works fine.Here is the result :

But in Lubuntu virtual keyboard looks like this :

I can see the output of virtual keyboard in Xubuntu and Ubuntu but i cannot see in Lubuntu.

What could be reason for this bug and how can i fix it ?