I had been on a Win7 x64 system for many years using both DF and lotus 1-2-3 with no problems, before switching to Actual Multiple Monitors for reasons I can't even remember. Then last week I did a clean install of Win8.1 and two days later win10 (both clean installs) and re-installed my applications and tweaked the OS to my liking and figured I would try the DF beta to see what it has that is new. Everything was fine for a week until today I tried editing a chart. Now, when I am working on a chart within lotus 1-2-3 and I double-click on the text title of the chart in order to edit it, the 1-2-3 application crashes. So I tried de-selecting the 4 or 5 programs I use as windows start up programs and tried again, and this time there was no crash. Then one by one I re-enabled the start up programs and this is what I found:

When DF is running, double-clicking on a chart title within lotus 1-2-3 always causes 1-2-3 to crash.
But if I exit DF or never load it at all at startup, 1-2-3 does not crash when I click on a chart title.

So I uninstalled and re-installed both programs, but that did not help anything. Then I tried renaming LTEDN40.DLL just to see what would happen and when then I started lotus got a fatal error with the message "Tool Module Not Found".

This behavior did not happen when I was running win7, only this new install of win8.1 or Win10. DF itself is not crashing here, just lotus 1-2-3. A cut-and-paste of the output from nirsoft's Appcrashviewer is below. BTW LTEDN40.DLL is a file within the lotus\compnent folder. Any advice is appreciated!

Problem signature:
Problem Event Name: APPCRASH
Application Name: 123w.exe
Application Version: 9.8.208.1200
Application Timestamp: 3d577a29
Fault Module Name: LTEDN40.DLL
Fault Module Version: 4.0.0.1203
Fault Module Timestamp: 36625bbb
Exception Code: c0000005
Exception Offset: 00007972
OS Version: 6.3.9600.2.0.0.256.48
Locale ID: 1033
Additional Information 1: 47bd
Additional Information 2: 47bd4076ab1f32620ccd1aa470aa8426
Additional Information 3: 34d5
Additional Information 4: 34d5c33c85ed1e9ba7a2c86ddb9ff92f

Note: The above problem is identical whether I am using DF or Actual Multiple Monitors. Lotus 1-2-3 is stable during a chart edit only when neither is running when the OS is 8.1 or 10. On Win7 everything is solid no matter if DF is running or not.

Any advice or workarounds are appreciated! Thanks!

"On the DisplayFusion Settings > Compatibility tab, can you try adding a rule for Lotus 1-2-3, and in the rule, enable the Disable Application Hooks"

Yes! That worked. Thanks a lot.

I have a different question about titlebar condensing, but will make a different post for that.