What are those blue lines?
Are you in the Page Template Editor?
Why does your score have a yellow background, as if it was a part?
Please switch to Engrave Mode to see your percentage of the page “fullness”. Adjust your Layout to have a larger paper size or smaller systems - so that the percentage is not above 100% and will show in green.
To input music switch to Write Mode and Galley View. You should not have a problem to input the caret there.
I still regret very much that I can’t write in my condensed layout. It’s nice to be able to see immediately how it will look later while you’re writing.
You can have two windows open on your project, one in Galley view and one in Page view, and switch back and forth.
The reason you can’t write into condensed staves is that their contents are auto-calculated from the individual staves. It’s a little like a formula in Excel – the way to change the output of the formula is to change the inputs.
You can open a second window on your project with Window > New Window, or Ctrl/Cmd+Shift+T. The two windows have different properties, so they can be in different modes or different views, but they reference the same underlying music, so changes in one are reflected in the other.
But only in the not-condensed systems. If something doesn’t work and then does after I open and close a different view, that looks very much like a bug to me…
Daniel, you can try to replicate your older Schott edition - or get pretty close to it.
Your “page fullness indicator” has to be be 100% at the maximum, so Dorico can layout your music. In your case as a first step go to Layout Options and start reducing the values for the inter system gaps.