Zoom changes on window resize

 I was able to fix this by going to View - Actual Size. 

After switching to "Actual Size", I resized the window and and it didn't zoom. I double checked by zooming to a different percentage then resizing the window and it seems to be fixed. 

The best way to get past this is to select something — anything — in your document.

By default, InDesign will move to the center of a selected page/spread whenever you change your zoom setting. So no matter where you are, when you, say, press Cmd/Ctrl+2 (depending on whether you're using a Mac or Windows system, respectively) to get to 200% display size, InDesign will move from whatever zoom percentage you were at, wherever you were in the document, to show you the center of the page/spread at 200% display size.

But if you want to see a specific area of your document at a larger/smaller display size, just first select it with your Arrow/Selection Tool and then choose your desired display size. For example, if you first select a picture at the upper-right of your page then pick that 200% display size, InDesign will then use the center of the image for a reference point and zoom directly to that image in the upper-right corner of the page at 200% display size.

On resizing the application/document window itself, you'll often see the same jiggling whether or not something is selected. InDesign is again trying to center your document in the new window space. But if you click on something and change the display size, from say Fit Page in Window view (keyboard shortcut Cmd/Ctrl+0) to Actual Size view (Cmd/Ctrl+1) the selected item will pop to the center of the screen at your chosen zoom display size.

A couple other zooming keyboard shortcuts you might want to try:

Cmd/Ctrl+4 - 400% display size

Cmd/Ctrl+5 - 50% display size

Cmd/Ctrl+Opt/Alt+0 - Fit Spread in Window

Cmd/Ctrl+Opt/Alt+Shift+0 - Entire Pasteboard view - your page/spread and all the surrounding pasteboard area around the document high/low and side by side

Master these keyboard shortcuts and you'll be an InDesign page-zoomin' demon.

Hope this helps,

Randy