Malfunctioning Cursor During Composition Of Text

[Echosyn618]

System in question is early 2011 iMac with Sierra 1012.6. Since about 2018 every time I compose text at websites, social media, in LibreOffice
and both email accounts and when using any of the browsers Safari, Firefox, Chrome and Vivaldi the cursor wats to delete every bit of entered text to the right of the spot where I click to place it, I have to use the right/left keys to get it to stop the highlight of the spot and put the usual line marker there so I can make my correction. I have asked several people in other locations and no person has yet provided a solution. If I need to reinstall Sierra I will do so under supervision from an expert. Mouse is Macally Dynamouse.

 

[DeltaMac]

I don't know if this is a solution, but just a setting to try out....
Go to System Preferences, then the Mouse pref pane.
Change the setting for "Double-click speed" to a slower setting. You could try almost all the way to the left. If that does not help, or makes it worse, then adjust toward the higher end.

 

[Echosyn618]

Thanks. I will try it. It was set at center point. Now it is set to10% from left so I test here bloom, baroom, dumdiddle. IT WORKS!! IT WORKS!! That is truly weird that it would do that and give me no end of irritation and grief when I compose text. It is as counterproductive as the obsession to always have background music or noise drowning out the dialogue or monolog in educational videos. Thank you so very much. I truly appreciate it.