When a windows forms TextBox reaches a certain length of text, it will start to appear empty in your form.
This is very simple to reproduce, but the exact number of characters (length) required to make the text disappear changes system to system - probably something to do with memory.
To reproduce this issue:
Create new Windows Forms application
Place 1 textbox, 1 label, 1 button on the form. Leave the default names.
Place the following code in the buttons click event:
for (int x = 0; x < 1000; x++)
textBox1.Text = textBox1.Text + "b";
label1.Text = textBox1.Text.Length.ToString();
Then run the app and hit the button until the text disappears. For me it was at 32000 characters.
Now... I need a way to stop that text from disappearing. We cannot set the textbox to multi-line for technical reasons - the textboxes in question are single line textboxes that sometimes exceed 10k characters, but only the first 50-100 characters are visible on the form... but we need those first few characters to be visible so the customer is not confused.
I am attaching a sample project.. tho it may be faster to follow instructions above and create a new one lol.