OS/2 3.0 introduced very tight tree spacing. This option permits user adjustment of the tree vertical spacing.
Note:
There is an anomaly with vertical spacing in the OS/2 tree control. If there is no folder icon used, minimum or zero tree spacing is based on the height of the font used. If the font used in the tree is less than the height of '+/-' box, then the boxes start to overlap. In this case, FS/2 will increase the tree spacing to prevent this but this causes an objectionable jump in the tree when a scan finishes and the tree spacing is applied. Use of tree folder icons will prevent this.
Also note that the FS/2 custom '+/-' box is overridden on first use by the default OS/2 box. The APIs for OS/2 support use of custom '+/-' tree boxes but fail to recognize that a custom box is in use. A workaround for this does not appear possible.