Configure button won't show on custom widget

I created a custom widget that won't show the configure button when I try to apply it to the page.

Why is that happening? The contents of the Configuration file is shown below.

<propertyGroup id="options" resourceName="Options">
	<property id="fragmentHeader" resourceName="CF_Title" dataType="string" defaultValue="${resource:Leaderboard_Name}" controlType="Telligent.Evolution.Controls.ContentFragmentTokenStringControl, Telligent.Evolution.Platform" />
	<property id="viewType" resourceName="View" dataType="string" defaultValue="full">
		<propertyValue value="full" resourceName="View_Default" />
		<propertyValue value="simple" resourceName="View_Simple" />
	</property>
	<property id="pageSize" resourceName="PageSize" dataType="int" defaultValue="10">
		<propertyRule type="Telligent.Evolution.Controls.PropertyRules.MinMaxValueRule, Telligent.Evolution.Platform" minValue="1" maxValue="100" />
	</property>
	<property id="showValue" resourceName="ShowValueColumn" dataType="bool" defaultValue="true" />
	<property id="showCurrentUser" resourceName="ShowCurrentUserPosition" dataType="bool" defaultValue="true" />
    <property id="selectedLeaderboard" resourceName="SelectedLeaderboard" dataType="custom" controlType="Telligent.Evolution.Controls.LeaderboardLookupPropertyControl, Telligent.Evolution.Platform" width="95%" />
</propertyGroup>