The emergence of ultranationalist sentiment in Cambodia following the box-office success of the Thai period romcom Love Destiny, or Bupphesanniwas 2, is very unfortunate.
Over the past several weeks, some ultranationalist elements in the neighbouring country have denounced the film, which stars Ranee "Bella" Campen, a well-known face in Cambodia, and Thanavat Vatthanaputi, the lead actor.
These extreme nationalists have called for the projection of Thailand's so-called "soft power" to be banned.
Leading the campaign against the film is Facebook page Academic Film Criticism, which has about 60,000 followers.
What is most concerning about the calls is the instigation of hate against Thailand, which is unjustified.
To begin with, Love Destiny is a love story between a young couple in the early Rattanakosin era, and there is nothing in the film about Cambodia. Nevertheless, the ultranationalists still made a fuss. For instance, the use of lamduan, a flower native to Southeast Asia, in the film's promotional materials prompted a barrage of criticism.
They said the flower, known in Khmer as romdoul, "belongs to Cambodia".
Netizens then uploaded photos of the flower to highlight the fact that it is Cambodia's national symbol, which was subsequently countered by others who said it can also be found in other parts of the region, including Thailand.
When the flower origins debate began, the film producer replaced posters featuring the flower with new ones.
What has happened on social media revives sad memories of the 2003 chaos that followed extreme nationalists' groundless accusations that a famous Thai actress claimed that Angkor Wat was Thai.
The actress never said that, but chaos ensued and Thai-Cambodian relations went downhill.
The hostility over the film that has triggered fierce debate on social media has worried even Cambodian academic circles.
Sambo Manara, a prominent Cambodian historian, is urging Cambodians to rethink ultranationalism, which he says is dangerous to Thai-Cambodian relations.
At the same time, some leading Cambodian filmmakers are also cautioning against extreme nationalism.
Previously, the Cambodian Culture Ministry dismissed complaints by the extremists about the film, downplaying its impact. But this may not be enough as the hate campaign has been continuing.
Such instigation warrants due attention by Cambodian authorities. If necessary, they must step in and nip this ultranationalism in the bud, or it may be too late.
As both countries share more than an 800-kilometre border and a long history, Thai-Cambodian relations have weathered many ups and downs. Lessons must be learned so that old mistakes are not repeated.
With a shared culture, the kind of competitiveness seen over the listing of a form of masked dance known as Khon in Thai and Lakhol Khol in Khmer, as Unesco intangible heritage, national pride is not unusual but it must be pursued constructively.
Both the Thai and Cambodian governments must focus on educating the public and do more to ensure their citizens adopt healthy attitudes.
There is no use at all in remaining trapped in past centuries. Instead, it is high time to seek the benefits that both countries can achieve by together, and move on with maturity.