Hi Chris,

> On Nov 10, 2018, at 3:05 PM, Chris Muller <asqueaker at gmail.com> wrote:
> 
> Hi Eliot, sorry for my ignorance -- I'm trying to understand if we are
> headed for a compatibility glitch between older images and newer VM's,
> or between older VM's and newer images.

Only compatibility between older images and newer VMs matter.  One should not expect to be able to run a new image on an older VM (since a new image may depend on  a new feature absent in older VMs).  One should expect to be able to run any (compatible) older image on a newer VM.  I think there should be no compatibility glitch because by default the new VM maps mouse wheel events to ctrl+shift+option+meta+arrow key, which correctly scrolls and avoids confusion with ctrl-arrow.

> 
> The old 5.0-201807260206 VM works fine even without any image changes.
> Is it possible to do the fix it solely in the VM?

But the old vm doesn’t respond to horizontal wheel events right?  Hence it dissent work just fine at all.

> 
> Best,
>  Chris
> 
> 
> 
>> On Fri, Nov 9, 2018 at 10:46 PM <commits at source.squeak.org> wrote:
>> 
>> Eliot Miranda uploaded a new version of System to project The Trunk:
>> http://source.squeak.org/trunk/System-eem.1046.mcz
>> 
>> ==================== Summary ====================
>> 
>> Name: System-eem.1046
>> Author: eem
>> Time: 9 November 2018, 8:46:04.222224 pm
>> UUID: 98d1a376-957e-40fd-ba0f-9e4893defad2
>> Ancestors: System-eem.1045
>> 
>> Add accessors for the sendMouseWheelEvents flag that instructs the VM to send mouse wheel events as mouse wheel events, not keynboard arrow keys.  Needs an up-to-date VM (and on WIndows needs the VM code to be written).
>> 
>> Fix a typo
>> 
>> =============== Diff against System-eem.1045 ===============
>> 
>> Item was changed:
>>  ----- Method: SmalltalkImage>>processHasThreadIdInstVar: (in category 'system attributes') -----
>>  processHasThreadIdInstVar: aBoolean
>>        "The threaded VM needs to know if the 4th inst var of Process
>>         is threadId which it uses to control process-to-thread binding.
>>         This flag persists across snapshots, stored in the image header."
>> +       aBoolean ifTrue: [self assert: (Process instVarNames at: 4) = 'threadId'].
>> -       aBoolean ifTrue: [self assert: (Process instVarNames at: 4) ='threadId'].
>>        self vmParameterAt: 48 put: ((self vmParameterAt: 48) bitClear: 1) + (aBoolean ifTrue: [1] ifFalse: [0])!
>> 
>> Item was added:
>> + ----- Method: SmalltalkImage>>sendMouseWheelEvents (in category 'system attributes') -----
>> + sendMouseWheelEvents
>> +       "The Cog VM can be instructed to deliver mouse wheel events as mouse wheel events.
>> +        By default mouse wheel events are mapped to arrow events.
>> +        This flag persists across snapshots, stored in the image header."
>> +
>> +       ^(self vmParameterAt: 48) anyMask: 32!
>> 
>> Item was added:
>> + ----- Method: SmalltalkImage>>sendMouseWheelEvents: (in category 'system attributes') -----
>> + sendMouseWheelEvents: aBoolean
>> +       "The Cog VM can be instructed to deliver mouse wheel events as mouse wheel events.
>> +        By default mouse wheel events are mapped to arrow events.
>> +        This flag persists across snapshots, stored in the image header."
>> +
>> +       self vmParameterAt: 48 put: ((self vmParameterAt: 48) bitClear: 32) + (aBoolean ifTrue: [32] ifFalse: [0])!
>> 
>> 
>