ListBox MultiSelect simulate always with Ctrl modifier?

dear community,

can someone check the ListBox MultiSelect Example from the documentation for me? It does not work for me, I can only select one item, not multiple at once

function multiselect
fig = uifigure('Position',[100 100 350 275]);

% Create Text Area
txt = uitextarea(fig,...
    'Position',[125 80 100 50]);

% Create List Box
lbox = uilistbox(fig,...
    'Position',[125 150 100 78],...
    'Multiselect','on',...
    'ValueChangedFcn',@selectionChanged);

% ValueChangedFcn callback
function selectionChanged(src,event)
    txt.Value = src.Value;
end

end

best regards

EDIT:

I noticed that I Have to press Ctrl for MultiSelect. How unconvenient.

Is there a way to modify inputs such that they are interpreted always as ctrl+left click?

Answer 1

[Jonas]

I tried to circumvent the ctrl modofier in such a way, that I look into the event's previous value and delete/save as necessary. Now, there is also always one option selected

I modified the callback as follows:

function selectionChanged(src,evt)

    prevVal=evt.PreviousValue;
    currVal=src.Value;
    
    if strcmp(fig.SelectionType,'normal') % to preserve ctrl behavior
    
        isThere=ismember(prevVal,currVal);
    
        if any(isThere)
            prevVal=prevVal(~isThere);
        else
            prevVal=[prevVal currVal];
        end
    
        src.Value=prevVal;
    end
end

please note that with the current state, the bahavior with ctrl left click changes and does not work as intended anymore.

EDIT: edited code to properly preserve ctrl click behavior