Steps:
1. Create a new Qt Quick qpp with default settings or open attached file.
2. Right click qml file change the first letter from lowercase to uppercase.(example:with main.qml file, change the "m"->"M")
3. Then press "Enter".

Excepted result:
File name should be changed (from main.qml to Main.qml).

Actually result:.
File name cannot be changed from a lowercase to uppercase, but can be changed to other letters .