Describe the Bug

Scrolling up and down the folder tree in large vpks (such as TF2's vpks) has a few seconds of lag time, including clicking the small arrow beside folder names to expand them.

Related to #280, but it was closed.

To Reproduce

1. Open tf2_misc_dir.vpk inside \steamapps\common\Team Fortress 2\tf
2. Expand the "materials" folder
3. Scroll up and down, click on folder arrows, etc.

VPKEdit Version

5.0.0-beta4

Operating System

Windows 11