Drop Shadow from filters not works on Subtitle generated text

[Sarvan]

I was trying to enhance the visual appearance of subtitle generated text, so i applied drop shadow filter looks like it doesn’t work, meanwhile i checked on normal text it works fine. Attaching images as reference

Did i miss any thing to apply any filter before this, please let me know.
If this drop shadow filter is not available for subtitle kindly add on next update.

[brian]

Correct. The Drop Shadow Video Filter only works on a transparent video track. This is because it works by inspecting the transparency of the alpha channel. And the output does not contain an alpha channel (or, more specifically, the alpha is all opaque).