I modified the Windows settings to increase the size of the scroll bar and it works great with iGrid.

Now I want to increase the size of the Tree Button but I cannot figure out the name of the setting that controls the tree button.

iGrid.TreeButtonSize

That only works if UseXPStyles is set to false. When it is set to true, I need to change the size in the Windows operating system.

I increased the size of the scroll bars by editing these Windows metrics in the registry: ScrollHeight and ScrollWidth.

My problem is that I do not know which Windows Metric controls the size of the treebutton.

Yes, you are right. If visual styles are enabled in your app, iGrid uses the system routines to draw many OS-specific elements - including tree buttons. As a result, you have the same look of these items both in iGrid and say in the Windows Explorer.

However, the drawing of such styled items is a copy operation for predefined glyphs that are hard-coded in the system resources. That's why we have no ability to change those metrics in the OS and our apps.

If iGrid does not use the OS visual style (UseXPStyles is False), the tree buttons are drawn in the iGrid code using our own routines. This allows us to set the desired size using the aforementioned property TreeButtonSize and even adjust the colors used in tree button (see the TreeButtonBackColor, TreeButtonForeColor and TreeButtonBorderColor properties).

I want to make sure I understand. You are saying that there is no Windows registry setting that I can edit to increase the size of the tree buttons? The only way to make them larger is to set UseXPStyles to false?

From my experience I know that this is not possible. If you examine such Windows API functions as SystemParametersInfo or GetSystemMetrics, you won't also find such a setting you can set programmatically.