Signal-Android/res/drawable/emoji_category_objects_dark.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android"
		  android:enterFadeDuration="200"
		  android:exitFadeDuration="300">
	<item android:state_selected="true">
		<bitmap android:src="@drawable/ic_lightbulb_outline_white_24dp"
				android:tint="@color/grey_400"/>
	</item>
	<item>
		<bitmap android:src="@drawable/ic_lightbulb_outline_white_24dp"
				android:tint="@color/grey_700"/>
	</item>

</selector>