Related to GUI

In GUI when user selects a particular plan ‘Plan 3’ and clicks on the ‘Delete’ button. Now assume that ‘Plan 3’ is currently being used. So, the application displays a dialog box to the user informing him that he cannot deletes this plan as it is in use. If the user can not use plan 3 , then who is using the plan 3? n why the user cannot delete it? Plan 3 is not your hierarchy? i confused. Sometime we want to delete any software from the system n we cannot delete it.

I will give you example of some database to understand this. A database is not used by single user. May be one user is viewing tables, another user is adding some data. When second user is adding data in a table, first user can not delete it because same table is in use. Similarly in this example, GUI is not supporting a single user. Multiple users are working on it. If you select any plan (for example plan 3) which is used by any other user. We can not delete it. Problem highlighted in this scenario is that plan which is being used by other should not appear in delete list because one user can't delete it if it it being used by other. This is one example of GUI mistakes.