Comment by aiilnns

I think it would be easier if there was no textbox, no click and insert text. Merely click, have a blinking cursor appear, write anywhere. After you've finished writing click again in an empty space and have the text box created, so you can resize it.

Similarly for drawing.

Ditch the boxes altogether while writing/drawing and have them appear afterwards for manipulation.

edit: Other than that your program looks quite promising!