Org file looks like following:
when cursor is at beginning of file, `org-forward-sentence' goes to the end of "my line.", which does not seem to be correct (heading is special outline). Then calling `org-backward-sentence' behaves correctly, ie it goes to the beginning of "my line.".
To workaround the problem I kept on inserting dot at the end of each heading. Until yesterday where I wanted to add link to heading from another file. When dot is at the end of heading, then adding dot to the end of link does not work.
correct behavior of `org-forward-sentence' would probably fix the problem, ie I could remove dots from ends of all the headings