Set up drill through correctly

Question

When I use a Power BI report, it seems to remember the slicer values I set last time I used the report. For example, there is a (textbox) slicer for product line on the report. Last time I ran the report I had selected Bicycles. When I open the report now, Bicycles is automatically there. Seems nice until I want to use the report as a drill through target.

I have a report that needs to be able to run stand-alone or as the target of a drill through from another report.

I followed Microsoft's instructions to create a drill through, but the target report is not behaving as advertised.

From the source report, I select product line = Clothing and use the drill through. Now I have Bicycles in the slicer and there's a filter for the page showing Clothing. My filters for my main viz are now:

Product Line
contains Bicycles

Product Line
is Clothing

Naturally, my main viz shows no results.

In fact, the filters on the slicer now includes

Product Line
is Clothing

But the textbox in the slicer shows Bicycles.

How can I force a Power BI report to start with slicers initialized to not have values yet?

Also, I notice that the drill through filters on the target now include everything from the row I selected in the source report. In the target report, I selected Drill through | Keep all filters = Off, but that doesn't seem to matter.

What is the correct process for configuring drill through between Power BI reports?

Please don't respond with "use a drop-down, not a textbox slicer". Using the textbox is a deliberate part of how I am meeting the users' need. My actual report is more complicated than what I have described above.

Side question: Is there a Power BI Fiddle site that can be used to create sample reports to provide clear, complete examples based on standard sample data to support questions like this?