RAUB Score for PC

Counting score in the card game called "Raub"
Rules of the game can be found here: https://www.pagat.com/rams/raub.html or on other web pages.
Points are added or subtracted by a click on the buttons.
Scores are showed in two places, by each player's name and in score rows, where scores from all players are showed.
When all points for all active players have been adjusted, button "Enter Scores" should be clicked, and then new scores will be showed in one new row.
When "New Line" is clicked, row with underscores will be added, which means that in next game round, points should be doubled (not automatically by the app).
When "Double" is clicked, currently entered points for the current game round are doubled, and then button "Enter Scores" should be clicked for saving them. This can be used for easier points entering when the game round is on doubled scoring.
If a player is not active in some dealing, then star symbol is added next to his score. This is useful when checking how many times have a player missed dealing rounds in succession.
Application is checking if there is an error in entering score, by counting how many points are reduced for all the players in one game round. This should be 4 (or 8 if the game round is on doubled scoring, with one exception of 3 which was taken into consideration), and if not so, the error dialog is showed. Also, another error dialog is showed when scores for players with increasing scores have wrong scores (not according to the rules of the game). This checking can be disabled in Settings of the app (in a case the app is used in an use case other from the game "Raub"). Settings can be reached by clicking the gear icon in the top right corner of the screen. Also in Settings, there is the button "New Game" and when it is clicked, scores and scoring rows are defaulted. Buttons "Back" and "Exit the Application" are self explainable.