Introduction
Show/Hide 
is a feature used to hide certain columns or headers of the selected report. Here were are going to explain how this feature is used in different datablocks.
Cube Report
In a cube report usually the report is in form of chart. If we want to display it in grid mode then comes the feature for Show/Hide columns. It gives user option to display the desired columns as well as column headers. As in the screenshot below we can see we have two options at the top 1. Select/Deselect All (Here we can select r deselect all the columns) and 2. Show Column Headers (by default this is checked but if we don't want to display column headers then this option needs to be unchecked. We also have option to sort our columns. On the left hand side all column names are displayed in alphabetical order and on the right they are ordered as they are displayed in grid. In case we wish to change the order of display in grid we can simply drag the column name from left to right on the position where we want it to be displayed. e.g. In the screenshot below we wanted 'Hour' to be displayed at the top so we dragged it from left to right at the top-most position and in this process it pushed the 1st position column to the 2nd position.
Metric Grid
Drillthrough
Show/Hide Column here lists all the column names to select / deselect as well as a text box to search for column name in case list is very long.
Score Card
Scorecard already has standard set of columns and in case we need to hide any column or column header we can use show/hide columns.
Generic Grid
This is similar to Cube Report show/hide option.
Spreadsheet
In case if we select a report from "choose datasource" then the icon for show/hide columns appear and we can then select or unselect any column which we don't want to appear on our spreadsheet.