Trouble inputting values for bitmap image sizes in materials

I find that Rhino won’t take space or “/” in input fields for the sizes of texture images in the materials editor. Cutting and pasting a value from another input field doesn’t work. Is there a special trick to inputting these values? Rhino 6.

For what it is worth: this will work when the UI gets changed to the Eto version, probably for v8.

In v7 you can already do this by changiing UI to the Eto version via advanced setting.