Hi all,
I’m experiencing a strange graphical artifact in Inquisit 7.1.5 (Windows) after an <openended> response trial. I have two openended trials in a row, each asking for two letters. After the participant types in the response and presses the continue button, the next trial starts correctly, but a thin gray frame/border remains at the bottom of the previous button/response box area and persists across all subsequent trials (see picture — the line next to the continue button).
Does anyone know how I can resolve this issue?

Here is a minimal snippet:
<text ls_1>
/ items = ("A X A Y B X B Y C X C Y D")
/ fontStyle = ("Arial",5%)
/ position = (40%, 50%)
</text>
<text ls_2>
/ items = ("E E F G G H I I J K")
/ fontStyle = ("Arial",5%)
/ position = (40%, 50%)
</text>
<openended I1>
/ stimulusframes = [1=ls_1]
/ mask = ^[A-Za-z]{2}$
/ position = (67%,56%)
/ size = (5%,5%)
/ required = true
</openended>
<openended I2>
/ stimulusframes = [1=ls_2]
/ mask = ^[A-Za-z]{2}$
/ position = (62%,56%)
/ size = (5%,5%)
/ required = true
</openended>
<block ls>
/ trials = [1=I1; 2=I2]
</block>
<expt ls>
/ blocks = [1=block.ls]
</expt>