how to turn off this display in the command window?

I'm using the app-designer of Matlab to create an app. The below display keeps showing up on my command windows, slowing down my processing. I couldn't find anywhere I forgot to aded a ';' sign. Anyone has any clue?

app = 

  A02_QC_Tool with properties:

               mainWindow: [1×1 Figure]
                  dicPlot: [1×1 UIAxes]
                  alkPlot: [1×1 UIAxes]
                      Map: [1×1 UIAxes]
                 tempPlot: [1×1 UIAxes]
                  salPlot: [1×1 UIAxes]
                 pco2Plot: [1×1 UIAxes]
                   phPlot: [1×1 UIAxes]
                  oxyPlot: [1×1 UIAxes]
                  silPlot: [1×1 UIAxes]

[Rik]

Apparently something is returning your app as an output argument to a call. Do you mean this pops up every time you start your app, or does this happen during the running of your app?

[Leon]

Many thanks, Rik!

I just find the reason. I have a missing ';' in the below line:

app.QCcomments.Value = ''