@David-Fernandes ,
It depends on what you mean by “markers”. If you mean a bookmarked line (clicking in the bookmark margin, or Ctrl+F2 to toggle bookmarks), then one way, if you’ve got two bookmarked lines:
227c10c8-47b2-4055-97a4-9226508b0f01-image.png
F2 (
Search > Bookmark > Next Bookmark) to go to one of the two bookmarks
Ctrl+Shift+B (
Edit > Begin/End Select) to start the selection
F2 (
Search > Bookmark > Next Bookmark) to go to other bookmark
Ctrl+Shift+B (
Edit > Begin/End Select) to end the selection
→ it will be selected from the start of the upper line to the start of the lower line (so it will not include the full lower line)
8c3b76f9-07f7-4a30-a11c-405f92b9abf1-image.png
If you just have two locations, and can get to them in some other way, you can use the same Begin/End Select.
For example, if I have used the Search > Mark dialog to mark the 9 instances of morbi in my Lorem ipsum text, I could then use F3 (Search > Find Next) to get to the desired morbi mark, then Ctrl+Shift+B to start the selection, then F3 one or more times to get to another morbi, then Ctrl+Shift+B to select that region:
8876e9c0-362c-473f-a9eb-10074fe58c21-image.png
Either of these give some sort of “marker” and then select the text in between. To “isolate”, I assume you could copy/paste the selection to some other document or to some other section of your current document.
If this isn’t sufficient, you will have to explain more about what you want.