Time Range tab and Custom timespan of Graph

Our organization is new to LM, and I was working on an issue today that required looking at different time spans to see the delta over a week, month, and longer for a particular trend.

I noticed that the "Custom" option in the drop-down list above was grayed out, so I looked at other graph types and found they all were grayed out for Custom.  I consulted the Help topics but didn't find an explanation, so I contacted support.

They explained that prior to expanding the Graph, I could utilize the Time Range tab at the top of the page to specify my custom time span. At that point, Custom in the drop-down is enabled for selection and returns the specified range.

My two suggestions or request for enhancements would be to please trigger the Time Range screen (attached) upon selection of Custom from the drop-down menu, and also that after I viewed the Custom time span, if I selected any other predefined span (like Last 30 days), Custom was again grayed out, and I had to return to the previous screen to set it once more.  This made the process of viewing last 4 weeks, then 5, then 6 up through last 12 weeks very inefficient and ungainly to navigate through.