Hello, sometimes when i open claws the message list takes all the vertical space, leaving no space to the message view.
The message view can be toggled with the 'v' key, so it's very likely you pressed the key while it's being opened and it god processed as soon as the window is open. It's also possible you inadvertently toggled it before exiting, so the status is restored on next start-up. In any case and unless you have further info it's not a Claws Mail bug.
It happens a lot of times, i just can't reproduce it always. It's not that i toggle the message view: i have message list and message view, each of them take ~50% of the vertical screen space; i close claws, and when i open it again, as soon as it opens, often the message view has 0% of the vertical screen space, but i can restore it by dragging it up (which i could not do, if i toggled it off, before closing claws or after opening it again). It could be a gtk3 bug, and it could be a claws bug. Testing a bit more, i noticed that it's not claws writing wrong "summaryview_height" and "messageview_height" values in clawsrc file before i close claws: i copied clawsrc to clawsrc.1 while claws was running, closed claws soon after that, did "diff" against clawsrc and clawsrc.1, no diffs; then i opened claws again and, as soon as it opened, the message list had all the vertical screen space, the message view had none.
this should be fixed in git: https://git.claws-mail.org/?p=claws.git;a=commitdiff;h=0a833d4a9acf8f7f92e5809d372a8c96f526fa3c I was never able to reproduce exactly your issue, but believe this fixes it. Please test the git version if possible.