1. Spelling Error
Programmers don’t take care of spelling errors in the programs. But the customers will have the bad impression on it due to spelling errors. So the tester should find out that errors for fixing them.
2. Having Incorrect Element Name
Sometimes we may find incorrect names of the elements on the program. For example, the save button may work to edit functionality. It would be the vital mistake on the program if clicking on save button erase the data. So the tester should check whether any of the elements have an incorrect name.
3. Having No Cursor
Cursor points on the screen where should focus attention. It requires to show the computer still active and listening to the instruction provided by the user. Sometimes the programmer may forget showing the cursor on the screen.
4. Cursor In the Wrong Position
If the cursor appeared in the wrong position, it will be difficult to use the program correctly. You are unable to enter data if the cursor moves outside the data entry area.
5. Writing In Wrong PlaceWhile writing in text input area, may write in wrong place although the cursor is in the correct position.
6. Failure to Clear Part of the Screen
When the prompt message is displayed for few seconds, it will be cleared automatically or can be cleared manually. It would be confusing and annoying if the part of the message remains on the screen.
7. Failure to Clear Highlighting
In most of the programs, you can highlight the text for the purpose of copying it. Sometimes previously highlighted text not cleared and makes most confusing.
8. Messages are Displayed too Long or Very Short
In the program many prompt messages are displayed for a fixed time, then cleared automatically. This message should be displayed for the time that required for reading that message. Unimportant and short messages should be cleared sooner important and longer messages.
9. Incorrect Layout of Screen
Sometimes you may find an incorrect and ugly layout of the screen and containing elements on the web application or website which you are going to test. This may occur due to incorrect CSS coding, missing data or images.
10. No Close Button on Popup Window
If any popup window appeared while using an application, there was an option to close it. But sometime the programmer may forget to place the close button on it.
11. Showing Incorrect Cursor
While testing an application, the tester should also check whether the correct cursor types appear. It will be confusing to the user if I beam cursor shown over the button and pointer arrow for text input field.
12. Overlapping HTML Elements
Due to CSS or other coding error HTML elements may misalign or overlapped each other. The tester should observe each page carefully whether the elements are appearing correctly or not.
13. Changing Layout for Smaller or Larger Screen Size
Although the application appearing fine for some screen size, it may not work for smaller or larger screen size. So the tester should check the layout of the application for all the available screen sizes.
14. Required Fields are Not Marked
Most of the user input forms on an application may have both required or optional fields. It should be necessary to mark the required fields to notify the user which was required to be filled while submitting the form. In most of the application required fields are marked with astrick(*) symbol. The tester should check whether the required fields are marked or not.
15. Scrollbar Not Enabled Even Required
In an application, the scrollbar will appear automatically when the entered data overflows the screen size. But sometimes scrollbar may not enable even it was required to view all the data.
16. Drop Down Field Values Not in Sorted Order
By default in most of the applications values of the drop-down field are in sorted order. So the tester should check whether the drop-down field values are in sorted order or not.
17. Tab and Shift+Tab Not Working Properly
The application will be more user-friendly and easier to use if the Tab and Shift+Tab key can be used while using an application. So the tester should check whether the Tab and Shift+Tab functionality worked properly in the correct order.
18. Incorrect Fields are Highlighted in Case of Error
If any error occurred while submitting the form due to filed validation, those input fields are highlighted which have an error. The tester should check whether the correct fields are highlighted in case of error.
19. Drop Down List Options are Truncated
If the drop-down list value is longer than drop-down list, list values may truncate. The tester should check whether the list values are truncated or not.
20. Broken Images Appear
If any linked images are broken on the web application or webpage, you will find broken image icons on it. You should also check whether the broken images are appeared there or not. While testing, sometimes the images may not appear or does not appear correctly due to your slow internet connection. So you should confirm on your current internet speed checking with internet speed tester tools available online.
Here I have listed some of the most common GUI errors, that may occur on any applications. If you also know about any other possible GUI errors that may occur on the application, you are welcomed to mention them on the comment session below.