Highlighting - only part of document

[LJA 0]

I'm trying to highlight a document and can do so on part of it but when I try to highlight another section, it won't work, a large circle shows up instead of the line/section I want to highlight.

[AllainU 0]

Hello @LJA,

Thank you for reaching out to us through our Community Forums!

In order for me to further assist you with your concern, could you please provide the following?:
-Nitro Pro build (format is 13.X.X.X, e.g. 13.2.2.25) you are working with. You can find this out by clicking on 'About Nitro Pro' under the Help tab or you can go to Control Panel > Programs and Features.
-Does this happen with every file? If it is a single file, please send us the sample file (with sensitive information extracted) by sending me a private message so I can replicate it on my end. 
-A screen shot of the error message you are receiving and/or any important information. To find out how to take a screen shot, check out this link: https://kb.gonitro.com/knowledgebase/#/search/screen/000004108 

To send them via private message, hover your mouse on top of my name 'AllainU' and select 'Message'.

Thank you very much in advance and I am looking forward to hearing back from you.