MUI Select, top border doesn't show

Question

Could anyone please say what can be the reason for such behaviour of select field? I am a new developer on the project, and assume that someone has somehow changed it.

          <mui.FormControl style={{ width: '598px' }}>
            <mui.InputLabel id="label">{t('profile.student.transcriptScreen.selectCourse')}</mui.InputLabel>
            <mui.Select labelId="label" value={values.category ?? ''} name="category" onChange={handleChange}>
              <mui.MenuItem value={'MATH'}>Math</mui.MenuItem>
              <mui.MenuItem value={'ENGLISH'}>English</mui.MenuItem>
              <mui.MenuItem value={'SCIENCE'}>Science</mui.MenuItem>
              <mui.MenuItem value={'SOCIAL'}>Social Studies</mui.MenuItem>
              <mui.MenuItem value={'ELECTIVES'}>Electives</mui.MenuItem>
            </mui.Select>
          </mui.FormControl>

Answer 1

                <mui.InputLabel id="course-name-label">
                  {t('common:subjectCourseName', {
                    subject:
                      values.category === 'SOCIAL_STUDIES'
                        ? 'Social Studies'
                        : values.category.toLowerCase().charAt(0).toUpperCase() +
                          values.category.toLowerCase().slice(1),
                  })}
                </mui.InputLabel>
                <mui.OutlinedInput
                  name="name"
                  value={values.name ?? ''}
                  onChange={handleChange}
                  label={t('common:subjectCourseName', {
                    subject:
                      values.category === 'SOCIAL_STUDIES'
                        ? 'Social Studies'
                        : values.category.toLowerCase().charAt(0).toUpperCase() +
                          values.category.toLowerCase().slice(1),
                  })}
                ></mui.OutlinedInput>
              </mui.FormControl>

export const categoryOptions = [
  { id: 'MATH', name: 'Math' },
  { id: 'ENGLISH', name: 'English' },
  { id: 'SCIENCE', name: 'Science' },
  { id: 'SOCIAL_STUDIES', name: 'Social Studies' },
  { id: 'ELECTIVES', name: 'Electives' },
];

Answer 2

You're probably missing the label parameter to mui.Select . I also suggest you change id="label" and labelId="label" to something specific. It will help you and any other developer clarify what it is identifying, something like course-selection-label .

Try adding the label property:

<mui.FormControl style={{ width: '598px' }}>
            <mui.InputLabel id="course-selection-label">{t('profile.student.transcriptScreen.selectCourse')}</mui.InputLabel>
            <mui.Select labelId="course-selection-label" value={values.category ?? ''} name="category" onChange={handleChange} label="Course">
              <mui.MenuItem value={'MATH'}>Math</mui.MenuItem>
              <mui.MenuItem value={'ENGLISH'}>English</mui.MenuItem>
              <mui.MenuItem value={'SCIENCE'}>Science</mui.MenuItem>
              <mui.MenuItem value={'SOCIAL'}>Social Studies</mui.MenuItem>
              <mui.MenuItem value={'ELECTIVES'}>Electives</mui.MenuItem>
            </mui.Select>
          </mui.FormControl>

Sources:

MUI's Select Component as well as This specific SO answer