src/vs/workbench/contrib/terminal/browser/terminalGroupService.ts/TerminalGroupService/_removeGroup
class TerminalGroupService:	private _removeGroup(group: ITerminalGroup) {
		// Get the index of the group and remove it from the list
		const activeGroup = this.activeGroup;
		const wasActiveGroup = group === activeGroup;
		const index = this.groups.indexOf(group);
		if (index !== -1) {
			this.groups.splice(index, 1);
			this._onDidChangeGroups.fire();
		}

		if (wasActiveGroup) {
			// Adjust focus if the group was active
			if (this.groups.length > 0) {
				const newIndex = index < this.groups.length ? index : this.groups.length - 1;
				this.setActiveGroupByIndex(newIndex, true);
				this.activeInstance?.focus(true);
			}
		} else {
			// Adjust the active group if the removed group was above the active group
			if (this.activeGroupIndex > index) {
				this.setActiveGroupByIndex(this.activeGroupIndex - 1);
			}
		}
		// Ensure the active group is still valid, this should set the activeGroupIndex to -1 if
		// there are no groups
		if (this.activeGroupIndex >= this.groups.length) {
			this.setActiveGroupByIndex(this.groups.length - 1);
		}

		this._onDidChangeInstances.fire();
		this._onDidChangeGroups.fire();
		if (wasActiveGroup) {
			this._onDidChangeActiveGroup.fire(this.activeGroup);
			this._onDidChangeActiveInstance.fire(this.activeInstance);
		}
	}