Increasing number of columns in UITable runs slow on command.

I created a UITable with 6 default columns in the design view. My code allows user to switch two radio button entities. The first case reduces the number of columns to 5 and the second case increases the number of columns back to 6. The code works when I run (f5) case 1 or case 2 from startup. However, the app freezes when I switch from case 1 to case 2. But, when I debug and run by step, there is no error or freezing. How do I solve the problem of the app freezing when I increase the number of columns in UITable. That is, when I switch from case 1 to case 2.

The codes are,

switch button group
  case 1
    %create first row in table
    u = {1 0 0 0 0 0}
    app.UITable.Data = u
    %create subsequent rows. num is a variable with numerical value input by user
    for i = 2:num
    n = {i 0 0 0 0 0};
    app.UITable.Data = [u;n];
    u = app.UITable.Data;
    end
    %delete the 6th column
    app.UITable.Data(:,6) = [];
    u = app.UITable.Data;
    %rename column heading names
    app.UITable.ColumnName = {'a'; 'b'; 'c'; 'd'; 'e'}
  end
  case 2
    %create first row in table
    u = {1 0 0 0 0 0}
    app.UITable.Data = u
    %create subsequent rows. num is a variable with numerical value input by user
    for i = 2:num
    n = {i 0 0 0 0 0};
    app.UITable.Data = [u;n];
    u = app.UITable.Data;
    end
    %rename column heading names
    app.UITable.ColumnName = {'a'; 'b'; 'c'; 'd'; 'e'; 'f'}
  end
end

Answer 1

[Image Analyst]

What is the value of num?

And why do you have an end after the first case block? That end closes off the switch statement. Then case 2 is left without a switch statement. I'm surprised it even ran. I'd think you should have gotten a syntax error.

You can put fprintf() in there at key locations to tell what place you're getting to during runtime.

fprintf('Now I am about to enter the case 1 block of the switch statement.\n');
fprintf('Now I am about to enter the for loop.\n');
fprintf('Now I just finished the for loop.\n');

etc.