In order to determine what the problem might be we need to know the steps to reproduce the problem with the data set you included above. If you have imported data use the "Archive Project" to zip all of the data into one file. I have loaded your data and don't see anything suspicious.
When this happens open task manager and note the CPU usage. Occasionally we find a spot where the program is doing the same operation an unexpected number of times and it should finish at some point in the future. When this happens the CPU usage for TBC will be high.
You data set draws much faster when you toggle Show all lines as solid on.
tim