I'm new to Confluence. I love how I can copy and paste a table from a Numbers file into confluence at it keeps the formatting:

However, when I add a new column, the cell at the top gets a white background, and there doesn't seem to be a way to get the colour to match.
The closest colour is grey which looks odd next to the others:

Any suggestions? Can I either force the new column to have the same formatting as the existing ones when created, or manually apply the existing colour to the new cell?