Some users are finding that shortly after an auto correct, their screen is losing focus, forcing them to click back on the screen to continue composing their message. We are aware of this issue and working on a permanent fix. Sorry for the hassle.
The temporary work around is to disable your OS X auto correct. Please ensure you have enabled Mailplane's spell check via the Edit > Spelling & Grammar menu item.
If you have any questions, please don't hesitate to contact us directly at: firstname.lastname@example.org