Copying glyphs from one font file to another

Hi, I’m trying to copy multiple glyphs from one font to another. When I select and copy 15 glyphs (Command C) and then paste them into my new font (Control V), it pastes them fine. However, when I then go into them individually and adjust the new sidebearings with my new H master, the glyph disappears into a small red dot in the corner. What am I doing wrong?

Can you do a small screencast of that you are doing exactly?

And do you have any plugins installed?

Sorry, I don’t know how to create a screencast but I’ve included some images. When I copy multiple glyphs from one file to another, and then go into a specific glyph, change the side bearing from the current number to H, it dissapears into a red dot.

I have no plugins installed.

What version of Glyphs is that (the four digit number in the lower left of the info window).

You can make a screen recoding with the Quicktime Player app.