Select any text on the stage, but not in the Adobe web font you intend to remove, then select the Add Web Font button
right from Font Family dropdown menu and select here Adobe Fonts. This opens up the Add Adobe Fonts dialogue.
Switch to Selected Fonts (patience, it might take some time before the font listings appear). In this example the font Myriad Pro SemiExtended will be the one to be removed. Note that this font is the only one highlighted in blue (the others are in use and can't be removed in this situation). One click on that box will remove the font from both, here Selected Fonts and from your Font Family dropdown menu.
thank you very much. I'm just learning Animate from a Lynda.com tutorial. Things were going great until I was instructed to change a text item from static to dynamic, then choose a web front from Adobe Fonts. I could no longer test in a browser, and my font menu would freeze, not show the list of fonts. Not sure what happened but now I can start again. Thanks Klaus!!