Strange Thing I Noticed in Firefox

Hello,

Whenever I try to make new posts with Firefox, the blinking text indicator is not there in the input text area. I can type in it just fine, but I cant go back and delete the text I typed previously. Nor can I select a body of text and manipulate it. I can only add/remove text at the very end of the typed text. Do you guys notice this or am I the only one?