Online Documentation for SQL Manager for Oracle
When working in the Grid View mode, you can specify which columns of the current dataset will be visible. Click the button available in the top left corner of the data grid and select/deselect columns in the drop-down list to specify their visibility/invisibility.
For your convenience the possibility to change the order of the columns in the data grid is available. To reorder columns, drag a column header horizontally to a place in between two other column headers indicated with green arrows.