I'm running Message+ on Windows 10. The window that the app displays, either the list of contacts or for a specific chat, cannot be resized horizontally, which makes it very difficult to see long messages. It can only be resized vertically. Can you please allow us to resize these windows arbitrarily?
Try sending a message to Verizon Wireless via the app's Feedback option. Open the Message+ app, click on the three horizontal bars in the upper left corner of the display, select "Feedback" and submit the suggestion.
It sometimes feels like Verizon Wireless (and Verizon Core) are ignoring their Windows based apps while staying on top of the apps designed for the other platforms.