I can't enter cell data after generating a chart

[JeffLeites]

I'll try to keep this simple I have a workbook with macros. It works with a .txt file containing a date and an amount. The first sheet is called Controls. It has two push buttons.

The first button triggers code to read the .txt file and fill in a 2nd sheet called WorkPad with columns for the amount, and 10, 30, 60 and 90 day averages, then automatically display a Chart sheet with a line chart. I can click on the Control Sheet tab to redisplay the Control sheet.

The second button triggers code to read the .txt file and fill in the WorkPad with columns for monthly high, low and close amounts, then automatically display a Chart sheet with a HLC chart.

There is code for both charts to drop a certain amount of the first lines from the WorkPad so that the charts will only use x number of the latest lines to prevent too much data squishing the charts.

This has all worked fine for many years.

I just added code to allow me to enter a date on the Control sheet to stop reading the txt file after that date. That allows me to chart older data.

The problem is, when I click on the Control sheet after the chart has been generated, I want to be able to enter a new date, and I can't enter the date or anything else on the Control Sheet unless I open the WorkPad sheet, and then go back to the Control sheet. (The buttons still work) I came up with a workaround, which was to add a Reset sheet/tab. It's code has one line to activate the Control sheet. So it's doing the same thing as displaying the WorkPad sheet then opening the Control sheet again. SO either way I can enter into the Control Sheet again.

I thought it was a coding problem, but the strange thing is, when I run the same workbook on another computer, there is no problem and I can enter a new date into the Control sheet right after displaying the chart. This leads me to believe that the problem is not in the code, but perhaps an Excel option setting that is different from on one computer than the other. I just don't know which option it would be.

Any ideas?