In Preview, if the sidebar is opened (e.g. by toggling thumbnails on) when the window is below a certain width, then the window expands to accommodate the sidebar. I think this happens because Preview has some built-in minimum width for the document viewer panel; if you're too close to this minimum there isn't space to shrink the document area to make room for the sidebar. When it's closed again, the document area expands to take up the extra space - so, for example, toggling thumbnails on and off, or searching for something then clicking "Done", makes the whole window wider.

I find this really annoying, for what might be quite a niche reason. I use a window manager (Magnet) and the critical window width appears to be just a bit more than one third of the width of my monitor. There's a shortcut for sizing a window to take up the whole vertical third, but sometimes I'll stack two documents one above the other in the top- and bottom-halves of a vertical third, which I have to do manually. If I search inside one of the documents, the sidebar appears, my window is resized and I have to fiddle with the mouse to get it back in place. Also, it just seems somehow...I don't know, rude? of Preview to override my manually assigned window position. I wouldn't mind so much if the window went back to it's previous size when the sidebar disappeared again, but it doesn't. I am aware that this is slightly petty and neurotic.

Here's an illustration.

enter image description here Fig. 1 Happily working away

enter image description here Fig. 2 I search for something in my reference doc and - uh oh!

enter image description here Fig. 3 DISASTER

Is there a way to override the (putative) minimum width of the document panel in Preview? Or, can someone recommend a better window manager with customisable snap points?

1 Answer 1


Window management is, sadly, not a strong suit of modern macOS.

Fortunately, there are plenty of 3rd-party options: Rectangle, Amethyst, and Divvy to name a few.

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