You can use html to color what amounts to a table cell. It's a bit old school, but it works.
<html><table width=1000 height=1000><tr><td bgcolor=black><font color=black>X
The 'X' at the end preserves the cell height when it displays.
A window to demonstrate. Note that I added a column to put a friendly name into, and a custom property to retrieve it:
test_dropdown_color_2019-09-09_0755.zip (4.0 KB)
Thread for reference. I had a similar issue with a table back in 2009. Fire up the wayback machine!