Drawables.Draw() ignores WriteMask?

[GarthTB]

I need to add solid-colored rounded corners to an image. Specifically, I want to use a rounded rectangle to divide the rectangular image into inner and outer regions, overlaying a solid color on the outer region. The solid color includes an alpha channel, so when alpha is not at maximum, it provides partial transparency, allowing some of the original image to show through.

using ImageMagick;
using ImageMagick.Drawing;
using static ImageMagick.CompositeOperator;
using static ImageMagick.MagickColors;

using MagickImage img = new("lena_std.tif");
var (w, h) = (img.Width, img.Height);
var r = .3 * Math.Min(w, h);
using MagickImage mask = new(Black, w, h);
new Drawables().FillColor(White).RoundRectangle(0, 0, w, h, r, r).Draw(mask);
img.SetWriteMask(mask);
using MagickImage colorLayer = new(Aqua, w, h);
img.Composite(colorLayer, Over);
img.RemoveWriteMask();
img.Write("lena_std_mod1.tif");

It works. But to reduce memory usage, I want to use Drawables instead of colorLayer.

...
img.SetWriteMask(mask);
new Drawables().FillColor(Aqua).Rectangle(0, 0, w, h).Draw(img);
img.RemoveWriteMask();
img.Write("lena_std_mod2.tif");

The result is a transparent center and solid-colored corners, without anything of Lena. Is Drawables.Draw() supposed to ignore WriteMask?
Apologies for posting this in Issues by mistake.
Magick.NET version: Magick.NET-Q16-x64 14.10.3
Environment: Windows 11 26200.7922, .NET 10.0, C# 14.0
Images:
lena_std.tif
lena_std_mod1.tif
lena_std_mod2.tif

[dlemstra]

Already answered here: #1963?

[GarthTB]

Thanks, I saw your answer. I moved it here for others who might run into the same problem, and to see if there are other implementation ideas.