When selecting text in a formula, if you make this procedure: 1) Select some text of a formula with the mouse. 2) DONT release left button yet, but move the mouse pointer below the formula textbox, just a little outside until pointer changes to a "not allowed" symbol. 3) NOW you can release the button. 4) Without clicking, move the pointer side to side over the text. 5) You will see the bug, it must be killed! Ok, now the pointer is selecting the text without the mouse button being clicked.
*** This bug has been marked as a duplicate of bug 145248 ***