Ibrahim,
You will have to make changes to the TabTheme\widgets\SidebarController\Widget.js and the TabTheme\widgets\SidebarController\css\style.css
Widget.js (version 2.1)
Line number to change is followed by changed code for that line #
135: var nodeWidth = (this.getWidth() - 2 - 21 - 18 * 4) / 6;
145: margin = box.h / 6 - 44;
168: if (allIconConfigs.length <= 6) {
172: iconConfigs = allIconConfigs.splice(0, 5);
295: if (idx < 5) {
697: var tab = this.tabs[5];
705: var nodeWidth = (this.getWidth() - 2 - 21 - 18 * 4) / 6;
style.css (add css rule):
.jimu-widget-sidebar-controller .title-node:nth-child(6) .tab-indicator{
background-color: #0d8005;
}