IME input in wrong position

**Describe the bug**
Candidate window of input method is at wrong position on Linux. The window is **always at the left bottom side** of the application.

**Setup**
Please complete the following information along with version numbers, if applicable.
- OS: Arch Linux with KDE Plasma Wayland
- Shell: fish
- Terminal Emulator: konsole
- Terminal Multiplexer: none

**To Reproduce**
Steps to reproduce the behavior:
1. Clone the repository
2. Build the example like textinput, textarea
3. Run the program
4. Try to use input method like Fcitx5.

**Source Code**
Just the provided example code

**Expected behavior**
The candidate box following the cursor.

**Screenshots**

**Additional context**