View used AllowsTransparency And DropShadowEffect Causing UI Stuck

There is a WPF program using CM Framework 3.2. I have a replay.xaml page that displays two images and two timestamp texts every 30ms to play back videos in a modal manner.
When using the AllowsTransparency and DropShadowEffect properties on the page, opening multiple replay.xaml pages can cause the UI to refresh slowly and become sluggish.
After I delete the relevant code of AllowsTransparency and DropShadowEffect only in replay.xaml, opening multiple replay.xaml pages will not cause the UI to become sluggish.
My display settings in the code are:
AllowsTransparency = True;
Grid.Effect>
DropShadowEffect ShadowDepth="0"
BlurRadius="5"
Opacity="0.9" />
Grid.Effect>