How ro decolorise a glyph

Accidentally I colorized a glyph. I want to remove the color to avoid redoing the glyph. Where is the decolourise command once I right click the glyph? Is it missing? The manual says that it should be there.
Is there another way of decolorizing the glyph without redoing it from scratch?

The undo command does the trick, unless you’ve made more changes after you colorized the glyph.

Otherwise, right-click within the glyph edit window, and then click Color → Decolorize. This option is only available in color mode.
Decolorize.png
If you need to decolorize multiple glyphs, do select all glyphs within the Font Overview dialog, and then right-click to select Color → Decolorize.

Thank you Erwin. I obviously did not look well enough.