After upgrading to Yosemite 10.10.5 (from Snow Leopard, using a Mac Pro 2009), I found Mac Mail almost unusable, because, especially when editing previously written text, the insertion point was displaced by several characters from the place characters or deletions actually occurred. It was driving me completely crazy, to the point that I was having to compose texts in another application and paste them into Mail - ridiculous that this should occur with such an elemental application from Apple. In my case, it was not, as far as I could see, anything to do with apostophes in particular. I tried various remedies, including repairing permissions, turning off auto-correct, etc, all to no avail. When I observed the behaviour of the cursor, however, I noticed that there was a discrepancy between the width of the visible characters and the measure by which the cursor would advance, character-by-chartacter at the prompt of the right arrow key. So it looked like the cursor was taking its cue from some other font with different character widths. I then tried changing the message composing font (in mail preferences) from the default "Helvetica", to "Helvetica Neue". This seems to have done the trick. I conclude (guess) that the bug concerns Mail's activation of Apple system fonts, and may relate specifically to some confusion in the confusing world of Helveticas. I can't rule out the possibility that my font management software (Suitcase Fusion 6 - up-to-date for Yosemite), might possibly have a role in this, but Helvetica and Helvetica Neue are both Apple system fonts, which, as far as I know, SF leaves well alone, locked in permanent activation inside the nowadays more or less inaccessible System library. So my belief is that this is an Apple problem. LouisMac
