Is there a difference between a uipanel created with GUIDE and a uipanel created with the function?

I am making a GUI with GUIDE that involves adding an axes and legend for the axes to a panel. My problem arises when I try to add interactive functionality to my legend, specifically the Toggle Chart Visibility functionality shown at this link https://www.mathworks.com/help/matlab/creating_plots/create-callbacks-for-interacting-with-legend-items.html.

In my GUIDE program, I create the axes with the parent specified as the uipanel:

handles.ax1 = axes('Parent', handles.uipanel1, 'NextPlot', 'add');

And then later, I add a contour and a legend for the contour to the axes with this process:

contour(handles.ax1, peaks, 'DisplayName', 'Peaks Contour');

obj_handle = findobj('DisplayName', 'Peaks Contour');

handles.leg = legend(handles.ax1, obj_handle);

set(handles.leg, 'ItemHitFcn', @hitcallback_ex1);

The hitcallback_ex1 function is the same as in the example that I linked above.

I have also tried this process in the command window creating a figure and uipanel without using GUIDE and then repeating the process:

f = figure;
panel1 = uipanel(f);
ax1 = axes('Parent', panel1, 'NextPlot', 'add');
contour(ax1, peaks, 'DisplayName', 'Peaks Contour');
obj_handle = findobj('DisplayName', 'Peaks Contour');
leg = legend(ax1, obj_handle);
set(leg, 'ItemHitFcn', @hitcallback_ex1);

And this works perfectly. My question is, what is causing the GUIDE program to behave differently than the code I wrote in the command window and how can I make my program behave the same way? I hope my question was clear enough and I am happy to provide any other information that can help solve this.

Thank You