A toolbar is a section of a window that contains iconic buttons that lead to common functions of the window or application. Developers often put toolbars in their applications to make these functions more accessible. However, you may not see every icon on the toolbar when you launch the program or window. If you still have space on your screen, you can resize a toolbar in a number of ways, depending on the application. Resizing a toolbar is also necessary if you need to fit other window elements -- such as menu or address bars -- on the screen.
Right-click the toolbar you wish to resize and check if there is a "Lock toolbar" option or something similar. Make sure that this item is unchecked so you can freely adjust the toolbar's size. Click the item if you see a check mark to unlock the toolbar. Right-click the toolbar again and check if there are other options that you can use to resize the toolbar.
Click the "View" menu of the window (if it has one) and go to the "Toolbars" item or something similar. Check if there are options that you can use to resize the toolbar.
Place the mouse cursor in different areas of the toolbar and see if the cursor changes to arrows with pointed ends on each side. This icon indicates that the toolbar is resizable. Hold the left mouse button and drag in the indicated directions when you see this icon to adjust the toolbar's size.