Unable to change Interval start and finish

Hi Ben thanks for posting in the Lucidchart Community and apologies for the trouble you are experiencing with the timeline shape library! I am currently only able to reproduce the issue you are describing when I don't place the interval shape on top of a block timeline shape since it does not have a timeframe to refer to. When selecting an interval shape that was placed on a block timeline shape you should be able to select the date and time from the shape options (see screenshot).

Please make sure to use the block timeline shape as well as the interval shape. Should the issue persist please comment with a screenshot of the issue so I can see what you are seeing. Thanks!

For more information on timelines in Lucidchart please take a look at the Timelines article in our Help Center.  

Thanks. The block timeline shape worked and when I place an interval shape I can modify the start and finish dates. However while I can have one interval shape with a modifiable start and finish I am needing to add other interval shapes to illustrate other operations that may overlap with other intervals' start and finish times. I expanded the block timeline which moved the dates markers to the bottom of the page but now the interval shape that is within the block expands as well. 

Here's a screenshot of what I'm trying to do. The green interval works with the start and finish but the others do not as they are not on the block timeline. However if I add more like the green one on the time block then I have the lines to the right and left.

Hi Ben

Thanks for clarifying your issue. Unfortunately having overlapping time intervals is not currently supported. However we're always looking for ways to improve. Would you mind adding your use case to our feature request form? Suggestions submitted via this form are passed directly to our product development team.