Summary:
When the 'Details' button on an expense sheet is clicked the "Expense Details" pop-up is displayed. The pop-up screen has incorrect zoom level and it is not 100%, so all the details are not seen properly.
To see all the details on the pop-up screen, the zoom level has to be set to 100% or the size of the pop-up screen needs to be increased.  Check the print-screen "Expense Details.PNG" attached to the solution.

Resolution:
The issue is resolved after adding the Web TimeSheet website to "Trusted sites". Follow the steps given here to add a website to "Trusted sites" list.

1. Copy the Web TimeSheet URL.
2. Select 'Tools' > 'Internet Options' on the browser.
3. Select the 'Security' tab and click on the 'Trusted site' icon.
4. Click the 'Sites' button.
5. Ensure 'Require server verification (https:) for all sites in this zone' is unchecked.
6. Paste the Web TimeSheet URL in the 'Add this website to the zone:' section.
7. Click the 'Add' button and then the 'Close' button.
8. Set the 'Allowed levels for this zone: All' to 'Low'.
9. Click the 'Custom Level' button.
10. Scroll down to the 'Miscellaneous' category and ensure that the 'Access data sources across domains' is enabled.
11. Continue scrolling down to the 'User Authentication' category and ensure that 'Automatic logon with current username and password' is enabled.
12. Click 'OK' to complete the settings and again 'OK' to close the Internet Options window.
13. Close all open browsers.
14. Open a new browser and log into Web TimeSheet again.