SHORTCUT - WRONG BROWSER ICON

My wife uses XP. She uses Firefox as her main browser.

As a result, her desktop shortcuts show the Firefox icon.

She sometimes creates a new shortcut by dragging a link from the Firefox
address bar to her desktop . It shows up with the Firefox icon as it should.
But if she then drags that icon into a desktop folder, it will sometimes
change to the IE icon.

Sometimes these IE icon shortcuts cannot be removed except by bypassing the
recycle bin.

Anyone know why this icon flipflop would be ocurring?

Graham