I had an Inline Dialogue region with a page item being a Popup LOV. I needed to be able to select multiple values and be able to manually add more. But once I switched on multi-select the input field contracted to max-width 4px, the only way I found to fix that was to set the item to Stretch Form Item on and have it stretch out. But now came another problem. Now the manual entry was weird, you could only click on the first 4px(or the 4px after the last value if there were already values in there), and text you were writing was not visible until you stopped writing and clicked away.
So I was wondering how to fix this.
Running on APEX 19.2 btw, maybe this gets fixed in next versions
I found that if I hadnt set the Stretch Form Item parameter, max-width was set to 4px no matter what else I tried. If I did set it though, then flex-grow was set to 0.
So I just had the js that shows the Inline Dialogue fix this with a simple js command:
apex.item("P1_LOV").node.style.flexGrow = 60;
Its a simple fix, but it took me a bit to figure out so I wanted to show the answer here in case it helps anyone else