Dear Thomas,
Below different options might help you.
1.There is a new and nice feature available with TM 9.0(With latest FPM service pack) i.e If you enable the 'Suggest Values' property for any UI element,system will give you recently accessed/used data when you start entering the value.
2.Another nice feature i.e Maintenance of personal value list in F4 help. If you maintain personal value list, they will be displayed as hit list.
3. If you still want to customize the suggest values feature, probably you should check the FPM element properties. To do that, follow below steps.
Launch the component configuration in customizing mode (WD application - CUSTOMIZE_COMPONENT) -> Select the UI input field for which you want to set this behavior -> You will see properties/attributes of an element selected -> You will see one of the properties are 'Filter method' and 'Suggest values'. May be you can try to explore possible values(Contains search and Prefix search) for 'Filter Method' property.
4.If you still can't achieve, we might have to check programmatically if any possibility to achieve this by enhancing some objects.
Unfortunately we never get such requirement, so can't guide you exactly. But I could provide you above insights.
Best Regards,
Bharath.K