I think it's a pretty elegant solution, although I would suggest complementing it with a button to increase or decrease the size of the color swatches; I mean, if I had to manage a palette of 216 colors, for example in 18 columns, that would give me 12 rows of colors, and with the current resolution, I would only be able to display approximately 4 rows.
By the way, I just realized that if you resize the screen with the cursor and then use the maximize screen button (the button in the upper right corner), the work area is bounded to the window without maximizing, greetings, and thanks for your dedication!😉