User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Firefox/60.0
Steps to reproduce:
Not a duplicate of https://bugzilla.mozilla.org/show_bug.cgi?id=561243
FF 60.6.1esr - Attempted to bookmark https://docs.microsoft.com/en-us/windows/desktop/controls/edit-controls
But since I don't what the entire name I wanted to trim the "| Microsoft Docs" off the end of the name. I attempted to put the insertion point just before the "| Microsoft Docs" text so it could be deleted.
The edit box would not move the insertion point to where it should when I clicked the left-mouse button while inside the name edit-box. Instead the insertion point just jumped back-and-forth a few characters in the center of the widget. No matter where I clicked in the widget toward the right-end of it, the insertion point never moved (other than jumping back-and-forth a few characters). The insertion point moves fine with the arrow keys, but doesn't reposition properly on mouse-click.
When attempting to save a bookmark with a long name, if you attempt to position the insert-mark in the edit box by clicking in the name edit box with the mouse, the insertion point should move to where the mouse was clicked. (just like every mouse input in an edit widget has for the past 20 years)