The following steps are specific for the V276HL model 27" Acer monitor, however most Acer monitors have this feature that can be shut off.
Please locate the external buttons either on the front panel of your monitor, or on the back side.
These buttons will allow you to change the monitor settings following below.
Buttons 2 - Power (turn monitor off and on)
Button 3 & 4 - "Down and Up"
Button 5 - Press to view menu. Also the "enter" button.
Button 6 - "Exit"
Button 7 - Ignore.
Press button 5 to open the menu.
Press button 5 again to open extended settings.
Navigate to the "Wrench" icon. Press button 5 to enter this menu.
Navigate to "Auto Source". Press button 5 to select "Auto Source."
Toggle "Auto Source" to "OFF".
Press button 6 three times to exit the menu.
Repeat as necessary for second monitor if applicable.