Cannot underline within an already highlighted segment as i could until latest version

Previously in Adobe Acrobat Reader i could select a segment of text, choose highlight, and then go inside the highlighted text and select a part of it to underline.  But with the newest version i downloaded last week, i cannot select text inside previously highlighted segment; trying just creats a line around all the highlighted text and allows me to delete it, but not choose a part of it.  I can begin selecting text from outside the previously highlighted text, but cannot begin selecting withing highlighted text.  What to do?

     Any help you can offer is deeply appreciated!