Preview field is flickering during writing

Same for me (MacBookPro late 2013, MailMate Version 1.9.6 (5318)).

Are there any news or comments concerning this issue?

No, it's a known issue and I'm still trying to figure out exactly why this happens. I'll let you know if I have something for you to try out.

Let me know if you spot some kind of pattern -- especially if something is needed to trigger it (although I assume you would already have told me). Just for the record, I haven't seen this issue on my own computer...

Thank you for your reply! I investigated a little more...

If the "generate html" option in the preferences is checked, there's no flickering, but html-code is always generated: [√] Generate HTML even if only for styling. When I uncheck this option, the flickering starts again. Here you can have a look at the settings causing the flickering: http://imgur.com/a/fZDHy

And by the way: Im using a MacBook Pro (13 Zoll, Mitte 2012) with mac OS Sierra.

@Benedikt: It's a bit surprising that disabling HTML generation would trigger the flickering, but I'll ask other users to try the same thing. For the record, I also tried replicating your settings, but I still don't get any flickering.

Just for the record, this started happening to me only after upgrading from Mac OS 10.11 to 10.12.
Version 1.9.6 (5347)

Just adding a screen recording of this (.mov)

For sake of clarification, this behaviour only occurs when an attachment is added.

I'm having the same issue - does not seem to make a difference if the "Generate HTML..." option is checked/unchecked - neither having attachments or no attachments. OSX 12.12.4 beta.

Thank you, it seems to work now with Version 1.9.6 (5366).

But - accidentally - a string with some numbers is always generated in the preview field (2AE883AA-33F3-4330-A544-A3B12C621468).

@Benedikt: Try updating again. I'm still working on scrolling behavior so don't expect that to work well.

I don't think flickering is fixed in general, but the problem appeared to have gotten worse with the latest Sierra release. I could reproduce one variant of the issue and that's the one I have fixed.

That seems to have done the trick. The preview window in version 1.9.6 (5347) no longer flickers while typing.

@Matt: I haven't done any changes related to this in r5347. It's only in the current test release: Hold down ⌥ when clicking “Check Now” in the Software Update preferences pane.

I see. I obviously hadn't tested it thoroughly on 1.9.6 (5347). I since realised that the issue recurred if the message included both formatting and an attachment.

Since I installed version 1.9.6 (5367) though, definitely no flickering!

Thanks for making the modification and for pointing out how to get the beta releases.

I'm running 1.9.6 (5347) and I still have this [rather annoying] flyckering...