FV - Slow UI response when resizing

Summary

UI response very slow when attempting to resize. This happens on both the Free Pascal IDE, and my application TParted: https://github.com/Kagamma/tparted

Note that this does not occur when running the IDE 3.2.2, or building tparted with fpc 3.2.2, so this is a regression introduced in fpc 3.3.1

System Information

• Operating system: Arch Linux
• Shell: fish
• Terminal: xfce4-terminal
• Processor architecture: x86-64
• Compiler version: 3.3.1-19958-g33fe3a02f3
• Device: Computer

Relevant logs and/or screenshots

See the following clip: https://youtu.be/tJcISA1dTrE

Steps to reproduce

• Open terminal and maximize the window.
• Runs the Free Pascal IDE in terminal.
• Open the editor.
• Attempt to resize it.

What is the current bug behavior?

UI response very slow when resizing.

What is the expected (correct) behavior?

UI response smoothly when resizing.