Colums gets partly deleted when deleting text in the column

Having a table with several columns while deleting text in a column we receive the following problems:

1. When you delete text with CTRL+DEL the last word right from the cursor is deleted but also 1-2 letters of the word left of the cursor.
2. When youre in the last column accidentially in the next row the first column is deleted and the other columns were moved left on the former place of the deleted column when you continue to use CTRL+DEL - but only for the row below the one you're editing, the rest of the table stays as is.