I'm not seeing this.
Click on package in the object browser. Source opens in editor pane.
Use up/down arrows. Focus changes in Object browser.
Click on Editor, use up/down arrows. Code scrolls as expected.
Alt-PgUp/Alt-PgDown cycles through the editor sub tabs
I forgot to mention I am using readonly mode.
Can you please check if it happens for you?
One more note: I use "autohide" setting for object browser, so it hides immediately as I open the package.
If I pin object browser, than focus never leaves it and up/down always change selected package in the object browser.
Yes, read-only mode behaves as you describe.
I've seen other posts that -CTRL-C for copy doesn't work in read only mode. It looks as if all the normal key definitions for a code editor are disabled or overridden when in read-only mode.