When going into the "Video Settings" menu in minecraft 19w08a, upon clicking the surrounding area (none of the buttons) you will no longer hear a clicking sound. That's great. But, if you change any of the slider options, ("Fullscreen Resolution", "Render Distance", "Max Framerate", "Brightness", or "Biome Blend") then you click the surrounding area, (no buttons) you will still hear the clicking noise like before. Clicking "Done" to exit the menu and then re-entering the "Video Settings" menu will fix the problem until you change another slider option. I have found that changing the "Mipmap Levels" option, while it is a slider bar, does not make the clicking noise start.

EDIT:

Upon further testing, I have discovered that this clicking noise occurs on every menu with a slider.
-Hitting "Options..." and changing "FOV" causes the issue.
-Changing anything in "Music & Sounds..." except "Show Subtitles" causes the issue.
-Changing any slider option in "Chat Settings..." causes the issue.

-Oddly, changing "Sensitivity" in "Controls..." *does not* cause the issue.