The other option, of course, is for @venky to start from scratch with a new UDL. Then build it up slowly, so that every piece is known working.
Here, I start with blah.txt, with the UDL editor docked. I switch to the default User Defined Language (so it really starts from scratch), Create New, give it a name (Second), and switch the active language for just this file to Second.
Then I go into keywords, use lowercase warning and give it a color, to show that it’s case sensitive. (I forgot while recording this second video that the screenshot above already showed the Warning case matched what was in the pasted UDL definition)
I go into the second keywords box with capitalized Warning, assign it a color, and watch the color change in the editor.
If a user is having trouble getting a UDL to work, I recommend starting from scratch, and building it up slowly, because then you can see each individual step work.