Resizing the game window causes content jitter

using UI Toolkit, I created two fixed-width visual elements.
When I build the game and resize the game window, the fixed-width visual elements also scale up and down rapidly, but then return to their fixed size afterward.
How to stabilize two fixed-width visual elements and prevent any jitter when resizing window?
Is the reason due to the issue of redrawing when the window is resizing?