Instead of tying the need for selection to opening of an application or activating a sheet, you can tie it to display or calculation of an object. For example, if display of values in a table, or bar chart makes sense only when any selection is made (such as display of order detail which requires an oder number, display of YTD value requires selection of year, etc.), you can add the condition for display of the object.
What you need to do is create Actions on the appropriate trigger events.
For document open go to Settings \ Document Properties \ Triggers and then select OnOpen and click the Add Action(s) button. Then click the Add button and select Selections \ Select In Field - in the Field box enter the field name and in the Search String box enter the value you want to set. Repeat this step for each field you wish to set.
The search string can contain a fixed value or an expression, for example to select the first item in a field alphabetically you will need to enter:
=minstring(FieldName)
Tabs also have triggers and these are set up in a similar way, right click the background of a sheet and select Properties then the Triggers tab. You can then click Add Actions to enter actions for entering or leaving a sheet.
I tend not to use triggers like this, particularly on sheet changes, as it can confuse the user - but if you have a good reason to do so then the above should help you out.
