Q: Lag in Typing in Yosemite's Mail w/ External Apple Keyboard

I just started poking around one day and this seems to work. Not sure why this would force it to work???

I just enabled Slow Keys under the Accessibility settings and typed out an email.  The lag did seem to be gone but I don't like how slow it makes using the delete key.  I'm back to using Postbox until Apple comes up with a fix to this bug.

and crazy to not have the caps lock key... (altho shift helps). still, some sort-of workaround for the moment. am leaving the System Preferences>Accessiblity>Keyboard window open, so i can turn on "Enable Slow Keys"...when i'm in Mail only. thanx R Meyer!

EDIT: for now, made an alias for the Accessibility pref pane, it's on my desktop. so quick access to that window...

Hopefully this might help Apple fix this many months long bug!!!!

I'm updating my open bug with them that this makes the lag disappear.  I can confirm that it fixes it for me but the loss of key-repeat OS wide is a killer for me.  I'm sticking with PostBox until Apple fixes it.

I just started poking around one day and this seems to work. Not sure why this would force it to work???

It seems completely in keeping with what many of us on this thread have said: it seems as if Mail (and only Mail) can't keep up with even moderately fast typists, and is caching characters. The cached characters then suddenly pop into view.

While this seems like an excellent demonstration of what the problem is--kudos for discovering it--I can't see it as a workaround. It's just too disruptive when typing elsewhere. Even if someone can come up with a macro that makes this change every time Mail is brought to the front, losing any keyboard functionality in a keyboard-intensive app like Mail is going to be a problem.

There's one observation that complicates the picture. Sometimes I notice Mail not displaying type and I just stop typing. Mail does not display the type in the cache after some time has gone by, but requires some input, like command S or space or something.

As to touch or hunt 'n' peck, I suspect this is worse for the better typists. By the time my brain has switched from composition mode to noticing that characters aren't appearing on screen, I've usually typed a few characters, including backspaces, etc. I'm a moderately fast touch typist and was a professional writer, so I never look at the keyboard, but am also never looking at anything I'm copying. I watch the monitor.

am just keeping that system preference open, but hidden. when i go to mail, i check "enable slow keys". a nuisance, but a minor one, compared with dealing with the lag. and better than nothing, until there's an actual fix...

There's one observation that complicates the picture. Sometimes I notice Mail not displaying type and I just stop typing. Mail does not display the type in the cache after some time has gone by, but requires some input, like command S or space or something.

...or wiggle the mouse/move the trackpad.  That has "flushed" the characters to the screen for me 100% of the time.

But it doesn't complicate the picture any further.  When the problem exists, it exhibits the behavior you described.  When the workaround is in place (slow keys enabled) that behavior disappears also.

An observation:

I was typing an e-mail with three large photos attached. I saw no lag in typing (probably just random good luck).

But I did happen to notice that while I was typing, the activity pane at the lower left showed both outgoing and incoming activity. No messages were queued up for sending, and no new messages came in during that time.

I've seen both outgoing and incoming activity before, but the striking thing here was that there were 7 outgoing messages showing and only one incoming. I assume that the outgoing and incoming activity is Handoff. But why seven outgoing?

Also, I've seen several times that messages with photos attached remain in Drafts, even after a successful send, and the message appears in Sent.

The Slow Keys is working great for me. Ahhh... thank you!

I'm only experiencing one side-effect: I tend to send messages using the keyboard shortcut (Command Shift D). Sometimes when I send with Slow Keys enabled, a "D" is typed after the end of my message, rather than sending.

But that's a minor price to pay to eliminate the amazingly annoying keyboard text entry delay.

What other issues are people seeing by turning Slow Keys on?

Kirk out

Key repeat is very slow with Slow Keys on.  Which means that backspacing a long ways is tedious.  Other than that, I agree that it works pretty well.

I agree that Slow Keys solves the problem.  The only new problem that comes with it is that key repeat rates are very slow, painful mostly for the backspace (delete) key.

Slow backspacing seems a small price to pay for forward-typing sanity.

Yay!

Kirk out

slow keys is great with mail, but still hope a fix comes before it's time for 10.11....

Argh!  It's back with a vengeance today -- slow-keys is turned on and I'm back to square one.  But I have more clues.  My keyboard appears to be frantically trying to determine what international character to type -- eg all the versions of "e" - è,é ê ë ē ė ę.  I don't know what this capability is called, so I can't figure out how to turn it off.  The other interesting thing is that the Keyboard Setup Assistant (the "change keyboard" option within the Preferences -> Keyboard) can't identify my keyboard.  It asks me to type a key to the right of the shift key, and then fails. So can somebody point me at the place to turn off that character-substitution function?