IME popup not showing in fullscreen when scale is set to 1

[sungyoonc]

Hyprland Version

System/Version info

Hyprland, built from branch main at commit fbdaf74a82b38e11a0a6914b3c9f7cb934ac1624 dirty (master: fix swapped workspaces (5397)).
Date: Wed Apr 3 09:22:59 2024
Tag: v0.38.0-10-gfbdaf74a

flags: (if any)

Bug or Regression?

Bug

Description

When the monitor's scale is set to 1, when in fullscreen the ime popup disappear but comes back when not in fullscreen

I tested this with alacritty, foot, kitty, thunar, obsidian, discord(flatpak, xwayland) but it did not happen in firefox(via text-input-v3) and okular(which use QT_IM_MODULE=fcitx env to access ime directly).

When I set the scale to anything except 1(e.g. 1.2, 2 etc), it doesn't have this issue.

This is my monitor config

monitor = eDP-1,2880x1800@120,auto,auto,vrr,1 (scale 2)
monitor = DP-3,1920x1080@60,auto,auto (scale 1)
monitor=,preferred,auto,auto

When I change the scale of eDP-1 to 1 the issue happens on it.
When I change the scale of DP-3 to 2, the ime popup doesn't disappear.

How to reproduce

1. Set the scale to 1.
2. Open an application (alacritty, foot, kitty, thunar, obsidian or discord(flatpak, xwayland) and presumably many others)
   If you want I can test other applications.
3. Type in a textbox -> IME Popup is visible
4. Go to fullscreen -> IME Popup disappears

Crash reports, logs, images, videos

ime_popup_1.mp4

ime_popup_2.mp4