If you position the cursor on an icon in the tree views of the project data navigators, a short information text (tooltip) about this icon is then displayed. If icons are combined (for example 
for a placed multi-line main function), a separate tooltip is displayed for each icon. No additional information is displayed for icons in other tree views (for example in the project management, in the part master data navigator, etc.).
Benefit:
The tooltips allow you to understand the meaning of the icons in the project data navigators faster.
See also
Icons in the Navigators