it would sometimes skip over words and start a new selection process. It would also not let me do fine selection on sentences, it would do it word by word. I was able to solve this problem with hints from the Interwebs: I opened System Preferences > Trackpad, and unchecked the box labeled 'Force Click and haptic feedback.' This solved my problem Good luck.
Its especialy difficult to select files for renaming, have had to repeat a number of times for the rename mode to come up.
It also expands folders or windows when I did not intend to do. other times its super sensitive, it create additional tabs of the link or it would take me 2 links forward or 2 links backwards depending on where i'm at on the website. Continue to hold until you hear the startup chime for the second time. If your mouse won’t drag, simply press the Esc key and the problem should be resolved. This is an unusual solution, but it works according to users. Expand Mice and other pointing devices, Right Click on the TouchPad, Click on Uninstall, Restart the Notebook twice, Check and see if the TouchPad starts to work for you now. I would have to select the hyper link 2 or more times to take. Restart the computer holding down the command - option/alt - P - R keys before the gray screen appears. Many users reported that they managed to solve left mouse button drag problems simply by pressing the Esc key. On selection, its a battle to get the selection I want. other times or move a window to another area, i'm dragging a file, it cuts out, picks up another file and gets dropped into an entirely different folder than was intended which I don't know where it went. other times it won't let me drag a file or a window to a different size. Combination of Click image block followed by a Drag mouse block may perform a double click as after Click image Drag mouse will also click on the block and. I am having trouble dragging and dropping files. CTRL+click+drag (Example: drawing perfect. Release the left touchpad button and SHIFT key when you are finished. Run the index finger of your other hand repeatedly across the touchpad diagonally. With the same hand, click and hold the left touchpad button. I tried the M510 to see if its a mouse problem, SHIFT+click+drag (Example: setting items on Layers 2 and 3) Hold down the SHIFT key.
I primarily use the M705 mouse when I had this problem.