With a shader pack on, borders, Wall Sina and the search area are now really visible, and they glow.
The full list of changes
01Shaders
0.28.4 changed how the borders are drawn under a shader pack, but they still did not reach the screen. Now they do: checked with Complementary on a test server.
Without a shader pack the borders look exactly as before.
Update the pack on your computer: the fix is in the client, and an old client can still join the server.