The problem has been partially solved, but still not completely.

When opening Document -> Paragraph and changing the interline space to 0.4fn and then press tab, the new setting is not applied.  Curiously, it is applied when using 0.5fn (which is one of the choices from the pull down menu).  Same for clicking inside another field.  The only way to get the new setting is by pressing enter.

TeXMacs 1.99.6
Tested on Windows 10 201803 (April)

Hello TeXMacs devs,
I recently noticed when I try to change the page margins then click on another field, the setting reverts to the last value, or if I'm changing page width or height, it doesn't actually apply until I press ENTER in that box. This happens on any new or existing document. The new value that I have entered into a text field or dropdown input box won't stick until I press "ENTER". I don't think this is good user experience because the user expects the value to be saved, and there's no indication as to how to save the new value.

For example, when I go to Document > Page, if I set page type to "user" in the list box, and enter "8.5in" in page width and then press ENTER, the cursor will move to the end of the text (probably because of how the control works, because it's usually an indication of a new line, but there isn't, so move to the end to show the user). The page size in the main GUI also changes (expected). However, if I then change this to "9in" and press TAB or click on another dropdown input box, the value stays the same, but the actual page width doesn't change, but the new value is not erased. This is expected behavior for it not being erased, but not expected for the page to have the previously entered value for width. If I click "OK" then reopen the dialog again, the old value is shown, meaning it wasn't saved.

Suggestion: If the input is invalid though (like "djsdj"), try interpreting it then maybe show a red X next to it to indicate an error and keep the value there for the user to change - if it's still invalid when the user presses OK in the dialog, don't change the value and revert to the previous one. (It depends on what LaTeX configuration you're using of course, this might be a good thing to have as a config option to enable/disable)

The other place where this happens is in the "Margins" tab. If I tab to another text box field instead of pressing ENTER, the previously entered value is overwritten by the input. For example, in "Margins on screen", the "left" value is 5mm. If I enter 10mm in that box then press TAB, 5mm is put into the "left" text box, overwriting 10mm which I had earlier. The TAB key does go to the next text box though, in this case, the "right" one. If I press ENTER instead after I write 10mm in the "left" box, if I then press TAB, 10mm stays in that box, and the actual margins in the GUI (on screen) have changed, which I would expect to happen even if I didn't press ENTER.

This is not documented in the TeXMacs manual either when I go to Help > Manual > Browse > Writing simple documents > Layout issues.

Please let me know if you need any further information regarding this issue.

Regards,
siliconninja