add: WMSetButtonEnabled(panel->okB, WMGetListNumberOfRows(panel->gcolL) > 1);
context: gradAddCallback(WMWidget *w, void *data){    TexturePanel *panel = (TexturePanel*)data;    WMListItem *item;    int row;    RColor *rgb;    row = WMGetListSelectedItemRow(panel->gcolL) + 1;    item = WMInsertListItem(panel->gcolL, row, "00,00,00");    rgb = wmalloc(sizeof(RColor));    memset(rgb, 0, sizeof(RColor));    item->clientData = rgb;    WMSelectListItem(panel->gcolL, row);    updateGradButtons(panel);    sliderChangeCallback(panel->ghueS, panel);}